Science of Love, Sex, and Babies

Who’s Turned On By Pregnant Women?

Posted in parenting, pregnancy, psychology, science, sex by jenapincott on September 26, 2011

 

Early one evening late in my second trimester of pregnancy, I was standing in the dairy aisle of the grocery store, with one hand on my back and the other over the kicking baby in my distended belly. A young man approached me, initiated a conversation about the World Cup, and, casually, asked me if I’d like watch the game with him that weekend. “You’re pretty!” he whispered. I was shocked.

I wasn’t putting out a sexy vibe. (Not at all.) I had assumed that any male attention I receive in late pregnancy, including that from my husband, would be friendly, not sexual. Why would a man who is not the expectant father think pregnancy is sexy? But then other women told me similar stories about how they got hit on in third trimester. So I decided to look into it, and it turns out that a study on sexual attraction to pregnancy has recently come out.

A team of Swedish and Italian doctors, led by Emmanuele Jannini and Magnus Enquist, recruited nearly 2,200 men who had joined online fetish groups such as alt.sex.fetish and alt.sex.fetish.breastmilk. They presented a questionnaire that asked the respondents questions about their preferences for pregnant and lactating women. The survey also asked for the sex and age of each sibling, and whether the sibling is a full sibling or not (half-sibling or adopted child). Most respondents reported both a pregnancy and a lactation preference. The average age at which respondents became aware of their preference was about 18 years.

What Jannini and Enquist and their colleagues were searching for was evidence that there was something special about the upbringing of men that are secually aroused by pregnancy. They knew that a specific stimulus early in life can elicit sexual behavior when theat animal reaches sexual maturity. For instance, goats that are raised by sheep are sexually aaroused by sheep only. This is called sexual imprinting.

Is it possible that boys that are raised by women who are pregnant for much of their childhoods are unusually attracted to pregnant women?

It turns out, what’s good for the goat is good for the guy. The more exposed a man was to his mother being pregnant and breastfeeding when he was between 1.5 and 5 years old, the more likely he is, as an adult, to be sexually attracted to pregnant and breastfeeding women.

A younger sibling is the key to early exposure. The respondents who eroticized pregnancy and breastfeeding had significantly more younger siblings than expected by chance. Respondents with one sibling were older than their sister or brother in 66 percent of cases. Interstingly, siblings born of a different mother does not appear to be related to respondents’ sexual preferences. Only a boy’s own pregnant mother seemed to leave a sexual imprint.

Freud’s “oedipal phase,” from about 3 to about 5-6 years of age, only overlaps partially with the sensitive period suggested by this study’s data, the researchers are careful to point out. Sexual imprinting is different in that it’s motivated not by sexual drive but because the individual learns what’s normal during a sensitive phase of development and later seeks sexual partners that resemble his (or her) own parents.

What does this mean for women who are pregnant or plan to be pregnant? It means you may be able to predict how attracted your partner will be to you in late pregnancy. Does he have sibling born within five years after him? If so, he’s likelier to be turned on by your pregnant self.

As for the guy I met in the dairy aisle, I’d wager he had a younger brother or sister. I’d bet more on getting this right than the winner of the next World Cup.

 *If you like this blog, click here for previous posts and here to read a description of my most recent book, Do Gentlemen Really Prefer Blondes?, on the science behind love, sex, and attraction. If you wish, check out my forthcoming book, available October 11,  Do Chocolate Lovers Have Sweeter Babies?: The Surprising Science of Pregnancy. 

 

 

 

IQ and Fish, the Whole Fish, and Nothing But the Fish

Posted in news, parenting, pregnancy, psychology, science, Sweeter Babies by jenapincott on August 30, 2011

For the nine-plus months of pregnancy, I dutifully downed fish oil pills. I had heard all about the virtues of essential fatty acids (especially DHA, docosahexaenoic acid), known collectively as omega-3s, which are found in fish such as salmon and sardines. These fats are involved in the development of new neurons and help form the cell walls — the structural support — of nerve cells. If the healthy brain is like a sponge, then the brain deprived of omega-3 is like a puddle.

Several years ago, in 2007, an enormous study funded by the National Institute of Health looked at the link between children’s scores on aptitude tests (at ages 6 months to 8 years) and their mother’s prenatal consumption of fish. It turned out that the kids whose moms ate fish more than twice weekly during pregnancy were significantly less likely to have low scores on cognitive tests. Low maternal seafood intake (two or fewer servings weekly) was also associated with increased risk of suboptimum outcomes for prosocial behavior, fine motor, communication, and social development scores. This was a huge deal. The nearly 12,000 expectant women who participated in the study were asked to record how much whole fish they ate, not fish oil supplements.

Naturally, this study — and smaller studies like it involving whole-fish consumption — inspired millions of pregnant women to focus on fish oil.

Problem is, not many of us want to or can afford to eat fish every day. Fears of mercury and PCB contamination are valid (many varieties of fish, such as tuna, have high levels that are toxic to fetuses). It’s not much of a stretch to say that fish oil pills are a better way to get your daily DHA.

But here’s the interesting part. Everyone has assumed that when it comes to omega-3 fatty acids like DHA, the source — whole fish or fish oil pills –shouldn’t matter.  Seems reasonable, but is it?

A few very recent fish oil studies cast doubt:

Results of fish oil pill supplementation range from neutral to negative…

A review of six clinical trials (1280 women in total) involving fish oil pill supplementation during breastfeeding found no significant difference in children’s neurodevelopment: language development (intelligence or problem-solving ability, psychomotor development, motor development. In child attention there was a significant difference. For child visual acuity there was no significant difference.  For language development at 12 to 24 months and at five years in child attention, weak evidence was found (one study) favouring the supplementation.

• At the Women’s and Children’s Hospital in Adelaide, Australia, researchers tracked the children of 2400 women who took DHA-rich fish oil pills in the last trimester of pregnancy. The use of these fish oil capsules compared with vegetable oil cap- sules during pregnancy did not result in improved cognitive and language development in their offspring during early childhood.

Other fish oil pill studies found disturbingly negative results:

• At the Universities of Copenhagen and Chapel Hill, researchers followed 120 Danish women who nursed their babies for four months after birth and took fish oil supplements (or olive oil pills). The children were tested in intervals up to seven years. The higher the early intake, the lower the child scored in speed of information processing, inhibitory control, and working memory tests. Boys whose mothers consumed fish oil had lower prosocial scores relative to the olive oil group.

Meanwhile, these recent studies strengthened the evidence that eating fish is brain-boosting:

• In a study that took place the Arctic, 154 11-year-old Inuit children took standardized tests for memory and verbal learning. Their scores were compared with their levels of DHA present in their cord blood at birth. Children who had higher cord plasma concentrations of DHA at birth achieved significantly higher scores on tests related to recognition memory processing. The source of DH in their mothers’ diets was fish and marine mammals. Intriguingly, the connection with higher test scores remained intact regardless of seafood-contaminant (PCB and mercury) amounts.

* A UK study of 217 nine-year-olds whose mothers had eaten oily fish in early pregnancy had a reduced risk of hyperactivity and children whose mothers had eaten fish (whether oily or non-oily) in late pregnancy had a verbal IQ that was 7.55 points higher than those whose mothers did not eat fish.

This is what I’d love to see: large studies that compare pregnant/nursing fish-eaters versus pill-poppers. Few researchers have tackled this, in part because we assume DHA works the same no matter how we get it, and because DHA from sources other than pills is difficult to measure or isolate.  Interestingly,  a study at the Norwegian Institute of Public Health compared height, weight and head circumference results of newborns whose mothers whose main source of DHA was fish versus pills.  They found that fish-eaters generally gave birth to larger babies while fish-oil-pill-poppers had newborns with a smaller head circumference.

Is it possible that fish consumption boosts IQ, but fish oil pills do not?

It’s dumbfounding, the difference in results between whole fish and fish oil. The researchers that found negative results of supplementation on nursing infants speculated on what goes wrong. It may be that early intervention with fish oil pills results in an “environmental mismatch” between prenatal and postnatal life,” (e.g. the fetus is “programmed” in the womb to live in an environment without abundant DHA and is thrown off when inundated with these fats later on).

Another theory is that the timing in these recent fish oil pill studies is off. The critical period in which fish oil may influence brain growth may be in the first trimester of pregnancy or toward the end of the first year of life — not during the time periods in which women in these studies were taking fish oil pills. It may be that DHA has a “sweet spot” — an optimum level below and above which may be detrimental to the developing brain. Indeed, when researchers look at fish oil pill supplementation and DHA-deficient premature infants, the results are much rosier.

There’s another compelling explanation of why fish oil pills don’t yield the desired results: DHA doesn’t do its magic alone. Nutrients and proteins in fish and seafood, other than DHA, may be  brain-boosters — or at least help us (and our fetuses or babies) to absorb or metabolize DHA better. All the fish oil in the sea can’t compensate for a bad diet.

In the US, a federal advisory recommends that pregnant women not eat more than two servings of fish weekly. This advice may be misguided given that fish such as salmon and sardines are high in DHA but low in mercury. Pop fish oil pills instead; they’re just as good– that’s been the message. But these recent studies point to a different truth.

Thus the case for fish, the whole fish, and nothing but the fish.

Food for thought.

*If you like this blog, click here for previous posts and here to read a description of my most recent book, Do Gentlemen Really Prefer Blondes?, on the science behind love, sex, and attraction. If you wish, check out my forthcoming book, Do Chocolate Lovers Have Sweeter Babies?: The Surprising Science of Pregnancy. 

 

Do You Live Less if Your Mom Was Stressed?

Posted in parenting, pregnancy, psychology, science, sex by jenapincott on August 12, 2011

Not long ago, a handful of scientists at the University of California at Irvine were curious about why some people live longer than others — even within groups that have similar ethnic and educational backgrounds, demographic and disease risk profiles, and are exposed to similar stressors in life.  At heart, they know the question is impossible to answer.  People are complex. The effects of life events on our genes—what we eat, what we breathe, who we love and how well we’re loved, and so on —are impossible to isolate.

But the scientists had a hunch that some of us had a bad start —beginning in the womb — because our mothers were highly stressed during pregnancy.   There’s an avalanche of evidence that women who are under extreme duress in pregnancy have kids who have shorter attention spans, lower IQ, memory deficiencies, and health problems.  

Could prenatal stress also set a baby’s life expectancy clock to tick faster?

One way to find out is to look at the genes of people whose mothers were extremely stressed during pregnancy. In each of our cells are DNA-protein complexes called telomeres, which cap the end of chromosomes.  Telomeres are like the plastic bit at the end of a shoelace to keep it from unraveling. Each time a cell divides, they become a little shorter. This makes telomeres something of a longevity marker. People with long tips at the end of their DNA strands tend to live longer than people who have short tips.  It doesn’t matter how long your shoelace is; what counts is the integrity of the cap.

In the UCI study, researchers recruited volunteers in their twenties. Some were selected because their mothers experienced a horrid event during pregnancy.  The scientists weren’t looking for the normal pregnancy stressors — work-life balance, weight gain, fretting about the baby’s health, and so on. They meant extreme stressors: a sudden divorce, a death in the family, a natural disaster, and physical or emotional abuse.

What they found is disturbing.

Compared to the control group (whose moms had a relatively stress-free pregnancy), people exposed to their moms’ extreme prenatal stress had significantly shorter telomeres.  By our mid-twenties, most of us lose about 60 base pairs of telomere length annually.  Not so of people who were exposed to extreme prenatal stress — they lose drastically more telomere length each year. The men had 178 fewer base pairs on average (equivalent to 3.5 additional years of aging).  Women had a shocking 295 base-pair deficit  (5 years of accelerated aging). It seems that a mother’s prenatal stress hits her daughter harder than her son.

How does this happen?  During pregnancy, stress may alter blood flow, oxygen, and glucose metabolism between mother and baby. High levels of the stress hormone cortisol from the mother flood the placental barrier. Excess cortisol may also slow down in the production of telomerase, an enzyme that acts as a repair kit for telomeres. Telomerase adds telomeric DNA to shortened telomeres. It regenerates our cells and tissues.  Like a fountain of youth, telomerase gives back what time takes away.

So what if you’re on a telomerase-less trajectory?

Here’s the big relief:  Your clock doesn’t have to keep ticking so quickly, even if it has been set that way before birth. There’s strong evidence that lifestyle changes can amp up telomerase production. One study found that stress management, counseling, and a healthy diet are associated with higher telomerase activity.  Another found that meditation turns up the telomerase dial.  

In the research community there’s much interest in the idea that, by maintaining our telomeres, gene therapy might someday reverse or prevent aging if started early enough.  Is it possible? As a measure to conceal the abuses of youth, teens could freebase on telomerase. 

Oh, the ways to stress out Mom.

 

 *If you like this blog, click here for previous posts and here to read a description of my most recent book, Do Gentlemen Really Prefer Blondes?, on the science behind love, sex, and attraction. If you wish, check out my forthcoming book, Do Chocolate Lovers Have Sweeter Babies?: The Surprising Science of Pregnancy. 

 

Assorted Trifles (from the science of love, sex, and babies)

Posted in news, parenting, pregnancy, psychology, science, sex by jenapincott on August 4, 2011

Research is like a box of chocolates; you never know what you’re going to find. An assortment of studies on love, sex, and babies — fresh from the lab.

Scientists found that men whose ring fingers are longer than their index fingers are likelier to have longer-than-average penises, at least among Korean men whose flaccid genitals were stretched under anesthesia. Studying the files of women who were raped in 1999-2006, French researchers discovered that there were fewer incidences of living sperm than in rape victims in previous generations, which supports the theory that sperm quality is declining. Women are likelier to get pregnant if they ovulate from their right-side ovary, visible by ultrasound, especially after two consecutive left-side cycles, inspiring women undergoing fertility treatment to desire a L-L-R pattern. Among women whose fetuses inexplicably died in third trimester, 64 percent (392/614) had a premonition before their doctors told them. They described a feeling of discomfort, of a strange unease; that they understood subconsciously that the baby would die. Many described how they dreamed of dead relatives and of death on the night the baby probably died. A recent fMRI study reported that women who had given birth vaginally exhibited greater activation in brain regions involved in the regulation of empathy, arousal, motivation and reward circuits in response to their baby’s cries compared to those who had not. Women who snore loudly and frequently were at high risk for low birth weight (relative risk = 2.6 [95% confidence interval = 1.2-5.4]), and fetal-growth-restricted neonates. The success of an IVF transfer may in part be predicted by how much glucose medium an embryo “eats” on days 4 and 5. On Day 4, female embryos consume significantly more sugar than males.

Are Men Likelier to Cheat When Their Partners are Pregnant?

Posted in parenting, pregnancy, psychology, science, sex by jenapincott on June 13, 2011

It’s bad enough that  Congressman Anthony Weiner had been taking photos of his naked self and sending them to women who weren’t his wife.  It’s worse when we learn that his wife is three months pregnant.

Aha, that it!, some cynics claim.  Now that Weiner’s oats are sowed, he’s exploring new (and, if the twittering teen rumor is real, very green) pastures.  It’s only natural.

But is it?  Are men really more likely to cheat when their wives are pregnant?

Turns out, the answer is that it depends on the man.

Reviewing the studies of pregnancy and sex, it seems there are three categories of expectant fathers. 

  • Type Z cheats or wants to cheat (the Weiners). 
  • Type Y desires his pregnant wife more than ever.
  • And then there’s Type X  — a man who has a decreased sex drive and a lower risk of cheating on his wife.

The bad news is that at least one study found that, yes, the risk of a given man to cheat on his wife increases during pregnancy, even if he is otherwise satisfied in his marriage.  His reasons? He may feel ambivalent about the pregnancy or the changes that go with it. His partner, especially in her first and third trimesters, may not feel like having sex.  Her sex drive may diminish. She may think her body is unattractive.

(Incidentally, bodily dissatisfaction happens to be the number one reason why most women have less sex during pregnancy.  Most of us think pregnancy is a turn-off for men.  That’s a misconception.)

But here’s the good news for pregnant women.  Fact is, many men — the majority as found in this study — desire their pregnant partner even more over the course of the pregnancy, even if they aren’t having as much sex as before. They find her as physically attractive as she was prepregnancy, if not more so. These are usually the Type Y guys. Another study found that, while couples had sex less frequently in third trimester, the only circumstances under which men change their sexual behavior is if they are older or worried about the safety of the fetus. (Note:  Sex does not raise the risk of miscarriage in pregnancies that are not high risk.) Otherwise, men desire sex with their wives just as much.

From an evolutionary perspective,this makes some sense.  Women benefited from having their mates around to help support them through pregnancy and childrearing. Sex helps men stick around.

The Type X expectant father – the one with a low sex drive and a lower risk of infidelity – may overlap with Type Ys. These are men who, at some point over the nine months, are afflicted with pregnancy symptoms:  nausea, weight gain, mood swings, fatigue, even vomiting. Hormones are the culprit.  These men have higher levels of prolactin, a hormone associated with sluggishness, weight gain, and bonding and parental behaviors.  Their testosterone levels plummet, making them less combative and sexually aggressive.

There’s an upside to Type Xs. It turns out that these faithful, fattening men display the most fatherly behavior when the baby arrives.  As new dads, they’re more likely to hear and respond to their infant’s cries.  They’re more compassionate and tolerant.  They make better fathers.

One might speculate that Weiner’s Type-Z behavior while his wife is pregnant doesn’t bode well for Weiner’s fathering instincts. It’s clear that if any hormone is raging in the man, it’s testosterone — not prolactin. He is probably not sharing his wife’s morning sickness and taking turns with her over the toilet.

There’s no crime in what Weiner has done; he’s just another politician more interested in power more than paternity.  But he is making us a little nauseous.

 *If you like this blog, click here for previous posts and here to read a description of my most recent book, Do Gentlemen Really Prefer Blondes?, on the science behind love, sex, and attraction. If you wish, check out my forthcoming book, Do Chocolate Lovers Have Sweeter Babies: Exploring the Surprising Science of Pregnancy. 

 

Do you carry DNA of former lovers in your body?

Posted in pregnancy, psychology, science, sex by jenapincott on January 28, 2011

This bit of science arcanum is especially cringe-worthy.

Many years ago, scientists first discovered that a large minority of women have Y-chromosome gene sequences in their blood. At first glance, this seems strange. Men are born with Y-chromosomes but most women are not. The male cells in these women must’ve come from somewhere else.

But where?

The most obvious source is a fetus. Nearly every woman who has ever been pregnant or had a baby has cells from her fetus circulating in her bloodstream. These cells filter through the placenta and reside in the mother’s bloodstream and/or organs — including her heart and brain — for the rest of her life. This condition is called microchimerism, named after the Greek chimera, a creature composed of the parts of multiple animals. Pregnancy-related microchimerism explains why women with sons would have Y-chromosome sequences in their blood.

This is fascinating enough. But how do you explain why women without sons also have male cells circulating in their bloodstream?

This was the subject of a study by immunologists at the Fred Hutchinson Cancer Center. They took blood samples from 120 women without sons and found that 21 percent of them had male DNA. Women were then categorized into four groups according to pregnancy history: women with daughters only, spontaneous abortions, induced abortions, and no children/no abortions.

While the number of women bearing male DNA was highest in the groups that had abortions (nearly 80 percent), women who had only girls or no babies (20 percent) also had male cells in their blood. For no apparent reason.

There are other reasons why women in the fourth group carried male cells: inherited in the womb from a male twin that passed, from a miscarriage they did not know about, from their mother via an older brother…

Or through sexual intercourse.

There remains a possibility, however remote, that cells from a lover may pass be transmitted during sex. Those cells may hang out forever in the recipient’s body, taking residence in any organ. These cells are the imprint of lovers past, a trace of living history.

Might a woman’s bodily fluids enter a cut in a man’s genitals as well? Could men carry around the genes of women they’ve slept with?

The imagination is stirred. What are those foreign cells doing in hearts and minds? Are they wreaking havoc in our heads? Do the cells of former lovers clash? In a science fiction scenario a person could even take a drop of her own blood, isolate a cell from her former boyfriend, and clone him. Then do with him what she will.

The upshot of this research? It’s yet another reason to use a condom.

“Cheating gene” mouth swab test available

Posted in news by jenapincott on May 8, 2010


In BLONDES and in this post I write about the so-called “cheating gene.”

Not long ago, Hasse Walum, a handsome post-graduate at the Karolinska Institute in Sweden, decided to study the association between a particular gene for what is called a vasopressin receptor and relationship stability. He analyzed the responses of over 550 twins and their partners to questions, some of them intrusive, about their relationships: How often do you kiss your mate? “Have you ever regretted getting married/moving in?” “Have you discussed a divorce or separation with a close friend?” “Rate your degree of happiness in your relationship on a scale of 1-7.”

Walum then sampled the men’s DNA. Getting DNA from the men was simple. You don’t need blood to have access to another person’s genome, just saliva, which the men submitted in a mouth swab.

What Walum discovered was stunning. Focusing on one particular vasopressin receptor gene variant, allele 334, he found that the more copies of it a man had, the weaker his bond with his partner. Men who lacked the gene variant were generally happiest in their relationships — only 15 percent of them had a crisis. Men with one copy were slightly more likely to have marital problems. And men with two copies were, on average, twice as likely to have had a relationship crisis in the past year than men who didn’t have the variant — meaning that 34 percent of them, or one in three, were headed toward a break up. Their partners agreed. Women whose partners carried one or two copies of the allele 334 variant were generally less satisfied with their men, probably because they generally scored as less affectionate than other guys.

Walum also found that men with two copies of the variant were nearly twice as likely not to marry their partners and mothers of their children as men who had no copies of the variant. This suggests that there is something slightly different about the vasopressin receptors in the brains of men who struggle in their roles as partners and fathers. These men may have more difficulty bonding with other people, including their wives and kids.

I imagine that some of you are now scheming to get an allele 334 test for your man. Of the more than five hundred women who responded to my online poll on this topic, nearly 65 percent said they would test their man if given the option.

And now you can. Yes, you can order a saliva test for allele 334 of the AVPR1A gene for $99 from Genesis Biolabs. (I can’t vouch for the lab. I’m reporting for entertainment purposes.)

Ladies, there’s a caveat here, of course. Even if there’s a correlation between this particular gene variant and a man’s behavior, it doesn’t account for all men. Just as the “god gene” and “gay gene” are met with skepticism in the scientific community, so is the “cheating gene.” Even within Walum’s study, there were men with two allele 334 variants who were happy husbands and fathers, and there were men without the variant who were miserable in their relationships. The statistics apply to populations, not individuals, who are also influenced by a other factors — parental role models, partner choice, opportunity to cheat, past loves, age, life satisfaction, religion, hormone levels, and so on.

A two-allele man may become a number one husband under the right circumstances.

But it’s your call. Swab him and then decide?

A new theory on men’s penis shape?

Posted in news by jenapincott on April 27, 2010

Several months ago, I blogged about a new theory on why men love breasts. New theories pop up all the time, so it’s no surprise that there are new theories on male body parts, too. A recent issue of Archives of Sexual Behavior features an alternative explanation for the shape of the human penis.

As described in BLONDES, the prevailing theory on why the human penis has a distinctive head and corona (rounded projecting border) is that it can scoop out semen deposited in the vagina by a woman’s previous lovers, thus averting a pregnancy. This means the last lover, not the first, gets the head-start.

Not likely, says Dr. Edwin Bowman, in his letter to the editor.

Instead of scooping out other men’s semen, writes Bowman, the penile head and corona scoop out vaginal secretions. After collected, these fluids are then absorbed by the foreskin. The mucous membrane of the foreskin, it turns out, is like a sponge for the stuff.

Why would evolution select for men to absorb vaginal secretions?

Just as semen has “mind control properties,” so do vaginal fluids. When ovulating and most likely to conceive, these secretions contain neurohormones such as pitocin and vasopressin. The latter in particular has been associated with bonding and is thought to trigger protective behavior among males for their partners. Vasopressin, after all, is thought of as a male “love drug.” Flooded with bonding hormones, a guy may be more likely to stick around if he impregnates his partner.

Knowing this, will more men use condoms?

Why do women get physically aroused and not even know it?

Posted in news by jenapincott on February 7, 2010

Some women seem to get turned on by almost anything man-on-women action, man-on-man, woman-on-woman, animal-on-animal, and so on. This is what sex researchers find when studying sexual arousal. When female volunteers are asked to watch erotic movies while outfitted with a plethysmograph, an instrument for measuring blood flow to the vagina, they often get very hot and bothered “down there.” Problem is, when many of those same women are asked to report how aroused they actually feel “up there” they often say they’re not turned on at all. Sometimes they even say they’re repulsed.

So what’s going on? Do women even know what turns them on?

Such is the puzzle that has plagued sex researchers for decades. And it’s a topic clinical psychologist Meredith Chivers and her colleagues address in a recent study, a meta-analysis of 132 papers on the genital measures of sexual arousal.

Why don’t women’s genital and subjective responses always agree? Here are a few theories the researchers present:

Women’s genital responses are hidden from view and produce less prominent somatosensory cues. While men may get turned on by feeling themselves get erect, women do not. However, [studies have found that] even when women received feedback about their level of vaginal engorgement, correlations (between genital and subjective arousal) were low and statistically nonsignificant. [Being told we’re getting turned on doesn’t necessarily turn us on.]

Women may edit their self-report of feeling sexually aroused because of socially desirable responding. Positive affect directs attention to erotic stimuli, thereby increasing sexual response, whereas negative affect interferes in the processing of sexual cues, resulting in lower sexual response. Lower concordance among women may reflect their experience of negative affect while watching the
conventional, commercially available erotica that is primarily produced for men.

Interestingly, the authors suggest that genital response to sexual stimuli may be an evolved self-protection mechanism:

Female genital response is an automatic reflex that is elicited by sexual stimuli and produces vaginal lubrication, even if the woman does not subjectively feel sexually aroused… Female genital response entails increased genital vasocongestion, necessary for the production of vaginal lubrication, and can, in turn, reduce discomfort and the possibility of injury during vaginal penetration. Ancestral women who did not show an automatic vaginal response to sexual cues may have been more likely to experience injuries that resulted in illness, infertility, or even death subsequent to unexpected or unwanted vaginal penetration, and thus would be less likely to have passed on this trait to their offspring….Reports of women’s genital response and orgasm during sexual assaults suggests that genital responses do occur in women under conditions of sexual threat. That women can experience genital response during unwanted sex or when viewing depictions of sexual assault suggests that women’s vasocongestion response is automatically initiated by exposure to sexual stimuli, whether or not these stimuli are preferred, and without subjective appraisal of these stimuli as sexually arousing or desired.

During processing of sexual stimuli, brain areas associated with emotional inhibition are activated among women… Genital responses are not affected by involuntary inhibition involving the anterior cingulate cortex, but subjective responses are. [Incidentally, women’s anterior cingulate cortex is most active when we’re ovulating and attracted to macho, high-testosterone men. The ACC is activated when you’re in conflict about something. Is this also a self-protection mechanism warning us to proceed with caution?]

Bottom line: Physical arousal is no proof a woman is really turned on. To really get a woman hot and bothered, you have to start from the top.

Rechanneling sexual arousal?

Posted in news by jenapincott on August 10, 2009

0_d321_3d4c4b52_XLScientists know exactly how to mediate sexual attraction between mice. Introduce males to females, and the brain region known as the anterior cingulate cortex (ACC) is activated. A new study has found that he neurons in the ACC are “fed” by a fusion of glutamate when a mouse is sexually aroused. Shut down the ACC with a sly drug and the result is a sudden loss of sexual interest. The drug used in the study was muscimol, the major psychoactive ingredient in some mushrooms such as Altamaria, and in mice it reduced sexual attraction within ten minutes of injection and lasted for about a half hour.

This is interesting because human attraction is also mediated by the ACC (as I describe in a previous post and in BLONDES). Researchers speculate the the ACC is involved in feelings of pain and pleasure and the evaluation of risk and reward. ACC activation affects our emotional state, leading to sexual behavior.

Is it possible to shut down our ACC with a drug such as muscimol (or a different drug without psychoactive side effects), and would it also temporarily make us asexual?

Bear in mind that what works in mice might backfire in humans. We may find that desire can overpower an addled ACC — there’s more than way to turn us on. For instance, sexual arousal of sorts is known to occur in a muscimol-induced dream state — although it often translates into a sort of cosmic awe. Some people apparently can have sex on psychedelics (although most popular ones are psylocybin-based, not muscimol); many can not. (Annie Sprinkle says that when she takes mushrooms (psylocybin) she doesn’t want to make love in a traditional sense, but found they can “deepen a relationship/”). It’s out-of-body sex. It transcends sexual arousal.

To get a real sense of the complexity of human sexual arousal we’d need human subjects — but even if volunteers are willing, certain experiments are unlikely to fly with ethics boards. Which brings us back to muscimolized mice, who, unbeknownst to us, may also be experiencing a sort of transcendental erotic phantasmagoria.

But a mouse couldn’t describe it as Annie Sprinkle does:

[Sex on psychedelics] was not about bodies coming together for physical sex, but about circulating sexual energy, which was everywhere and available just for the asking. I could tap into it just by tuning in and saying “yes.” I realized that everything was sexual/ sensual–that even all my little cells were all having sex. Sex was both microscopic and enormous.

Do beauties inspire higher sperm counts?

Posted in news by jenapincott on July 24, 2009

HughHefner Not all orgasms are created equal. For instance, intercourse orgasms are known to trump masturbatory ones, as evidenced by the amount of dopamine and prolactin produced. For men, sexual excitement produces higher sperm counts. As I recount in BLONDES, men who felt jealous or threatened by the possibility of a cheating partner had higher sperm counts than men who did not. The same is also true of male porn-watchers masturbating to a threesome. When guys watched two men attending to one woman, they had higher sperm counts than when watching one-on-one sex.

Sperm competition is the reason, according to the notorious British biologists Baker & Bellis. Men produce more copious, higher quality semen in situations in which those sperm might compete with rival sperm from other males.

And now there’s more — speculation that beautiful women also inspire men to have better quality sperm.

Female beauty has been found to enhance male sperm quality in other species. The latest evidence comes from a study led by Oxford biologist Charlie Cornwallis on Gallus gallus, a species of bird. Cornwallis and his colleagues discovered that the comelier the chick — e.g., plump with an elaborate comb — the better the quality her partner’s sperm (more motile, higher velocity, with a higher sperm count). Interestingly, this was true of dominant males but not subordinate ones, who appeared to put everything they had into every copulation. From Cornwallis’ perspective, the most fit males invest their best loads in the most reproductively fit females.

No study has yet proven that the same is true in humans — it’s not exactly ethical to recruit a guy to have sex with both a beauty and a plain Jane and then compare the aftermath. A beauty bias that affects sperm count may be true only in a wildly polygamous species, which humans are not.

Even so, this theory applied to humans doesn’t sound so controversial if you think about it — after all, sperm counts in men are associated with sexual excitement. Beauty can spark frisson. Even more exciting to ponder is how in practice an alpha male would make a larger reproductive investment in the most desirable mate. How does a Hugh Hefner decide? And wouldn’t it be ironic if this were true?

Nocturnal orgasms — women have them too

Posted in news, Polls and Surveys by jenapincott on June 25, 2009

For the 40 percent of women who’ve had one, an orgasm in a dream is often more intense that one in real life. And it’s not just a dream — a nocturnal orgasm is a real physiological phenomenon. The dreamer awakens to the same pulsing sensations she’d have during an orgasm from masturbation or sex. Her heart rate surges, her breathing deepens, her vaginal blood flow increases. Her orgasm might even be so fierce that she cramps up as she transitions from dream to reality.

Why?

A few studies shed some light:

1. During REM, the relative pulse pressure in the vagina increases. This also happens to a man’s penis, resulting in nocturnal emissions and morning erections. The content of the dream doesn’t appear to affect genital pulse — after all, it increases every time you sleep — but the physical sensation may influence your dreams (no one knows for sure). At the same time, the parts of the brain that inhibit orgasm, particularity the prefrontal cortex and amygdala, are offline when you’re asleep. (Readers of BLONDES might recall that the left amygdala, associated with anxiety, and the prefrontal correct are quiet during orgasm.)

2. Female orgasm can result from brain activity alone — “no hands.” Evidence of this comes from the research of Beverley Whipple, who studied women who reach orgasm via “self-induced imagery” (i.e. fantasy) alone. Volunteers’ blood pressure, heart rate, pupil size, pain threshold, and so on increase as they reach climax, their hands nowhere near their genitals.

As speculated by Whipple ( see also her research on paralyzed women), a “hands-off” orgasm may channel the vagus nerve, which is like a livewire that extends from the brain to the cervix via the heart, lungs, and other organs. Not every orgasm strums it — but, like hitting the right chord, a vagus nerve climax is said to be richer and more fulfilling. Some women think they can even feel it surge through their bodies from their brainstems. (See previous blog about asphyxiophiliacs.) It’s interesting: Vagus nerve activity might be one reason why so many women say their nocturnal orgasms are so much stronger than their diurnal ones.

Only in their dreams….

Why do women say chocolate trumps sex?

Posted in news by jenapincott on January 29, 2009

chocolaterex_468x481Ask most people what they lust after and the likely answer is chocolate. Ravishing a candy bar or a cup of hot cocoa, chocoholics claim to have chocasms. Chocolate lust is so intense that informal surveys in Europe and the United States report that about half their female participants prefer chocolate to sex.

One good explanation for this is that chocolate consumption is so often compared to sexual consummation, or a precursor thereof. But here’s the rub: there’s no proof that chocolate will lift the libido. If it has any amorous properties, they’re limited and vary from person to person. As detailed in BLONDES, chocolate contains neurotransmitters that might have a minor effect on the brain, but the scant amount in chocolate is rapidly metabolized. Chocolate is also a minor stimulant due to a caffeine-like property, and it contains the anti-clotting agent flavanol. Yes, it may be good for your heart, but researchers found no difference in sexual arousal between women who eat three servings of daily and none at all.

So why do many women say they’d rather unwrap a candy bar than roll in the sheets? Chocolate never disappoints is a glib answer, but there is something to be said for reliable pick-me-ups. The addition of sugar and fat in chocolate bars can raise your serotonin and dopamine levels, which lift your mood and energy levels. The stuff hits the reward-and-addiction circuits of the brain in the way that sex and other rewarding experiences do.

But why are there more female than male chocoholics? One theory is that serotonin levels are low in premenstrual women, and chocolate is a sweet way to perk ourselves up. (In fact, women’s desire for chocolate does seem to follow menstrual patterns.) But if that were so, wouldn’t any carbohydrate do — why crave chocolate and not candy canes? The answer could be that chocolate is unique. It has an unrivaled texture, aroma, and mouth-feel. It’s silken, sinful, and indulgent. Aided and abetted by (the serotonin-enhancing) milk and butter, it’s also a tactile marvel — it literally melts to your touch. It’s rich, complex, and sensual.

Perhaps the proper question is not how chocolate compares to sex. Ask instead how your lovers could be more like chocolate.

POLL: Love blockers –would you take them?

Posted in news, Polls and Surveys by jenapincott on January 14, 2009


Is this the end of love as we know it — exasperating, unpredictable, uncontrollable, and full of rogue potential? Does the future offer sex without emotional mayhem? Fuss-free breakups?

“Love is dead.” “Anti-love drug may be ticket to bliss.” Such are today’s headlines trumpeting the research of neuroscientist Larry Young. Dr Young and his team at Yerkes Research Center are best known for their studies on the love lives of more-or-less monogamous prairie voles. (In BLONDES I describe their fascinating views on the genetic and hormonal basis of bonding and what it might mean for humans. On a related topic, check out my cheating gene post.) The first question inspired by this research is “Can a drug make you fall in love?” The flip side of this coin is just as rich: “Can a drug prevent you from falling in love?”

For now it’s all speculation, but many researchers, including Dr Young, believe the latter is possible. (Fewer care to speculate on the former. Given how difficult love is to define, it’s easier to say you can prevent it than invoke it.) The gist of the idea is that a drug could short-circuit the biochemical pathways that flood the “emotional bonding regions” of the brain with neurohormones such as oxytocin and vasopressin. Just as morning-after pills work by preventing fertilized eggs from implanting, so the “anti-love drug” — oxytocin or vasopressin blockers — would prevent emotional seeds from taking root. Female voles who are given anti-love drugs can mate with a male dozens of times and fail to exhibit any of their usual bonding tendencies, no matter how affectionate the males.

What good is an anti-love drug? The possibilities abound. A few nasal puffs and a woman may more easily have “sex like a man,” feeling pleasure but free of the morning-after anxiety of whether he’s “all that into her.” People in addictive, abusive relationships could just pick up and carry on. Couples may have open marriages without emotional messiness. There may be fewer midlife crises involving trophy wives and umbrella boys. Sex would be only sex. The anti-love drug could be a temporary fix of sanity.

But would you dare take it — even on a short-term basis? At risk of throwing the poll above, my vote is no. What sort of human beings would we be without a range and depth of emotional experience? The angst and anguish of lost love. The self-mending. Even the melancholic savor. What would we learn about ourselves without it? Even in the twenty-first century I’d say it’s better to love and lose than never to love at all.

Women’s scent has mind control properties

Posted in news by jenapincott on January 10, 2009

bxp68578I was shocked by the overwhelming response (nearly 60,000 views!) to my post, “Semen has mind control properties.” Many readers said they think it’s a fascinating idea — that there are proteins and/or hormones in semen that subtly affect a woman’s sexual behavior. But what “secret weapons” do women have to “control” men?

I have a few responses, which are detailed in my book.

1. Women are (generally) the choosier sex. From an evolutionary standpoint, we’re pickier about our sexual partners because we have more at stake in the event of a pregnancy. Everywhere around the world, even in the most egalitarian countries, women desire fewer lovers than men do. Although women make trade-offs depending on their circumstances, we’re more about quality (even for flings). This by default gives women a sort of upper hand.

Now the sexier stuff:

2. Chemicals released during sex affect men, too. When he orgasms, his body releases vasopressin, a neurohormone associated with bonding (and drowsiness — it’s one reason why men fall into contented postcoital slumbers). This means that sexual intimacy may make a guy more attached to his lover. How likely is this? Intriguingly, a lot may have to do with his particular vasopressin receptor genes.

3. A woman’s scent may have mind control properties. Guys tend to prefer a woman’s body odor around the time she’s most likely to conceive (as described in BLONDES). On a subconscious level, men have been found to behave differently around this time of a woman’s cycle. According to studies such as this one at UCLA, women report that their partners are more jealous, loving, possessive, and attentive when women have high levels of luteinzing hormone in their system, a sign of imminent ovulation. In the famous stripper study, johns were also much more generous — paying up to twice as much — when the strippers were fertile. Scientists speculate that men are unwittingly responding to estrogen-related properties in women’s sweat and other bodily fluids. Men, meanwhile, are oblivious to why they’re acting so servile.

Bottom line is that there are no doubt many hormonal signals that give either men or women the reproductive upper hand. We’re all either sperm-zombied or pussy-whipped — that’s what some readers have quipped. But a sweeter way of looking at it is that these neurohormones also help give rise to love and long-term attachment. Not to say that chemistry could or should ever define love, but it does help explain some bonds.

Santa makes people jump in the sack

Posted in news by jenapincott on December 23, 2008

santababy_000There’s upside in a down economy — if you’re in the condom business. According to an interview with the condom manufacturer Trojan , their sales peak is the week between Christmas and New Years. Come Santa season, everyone seems to jump in the sack. (Here’s further proof of the “Santa effect.”)

What is it about Christmas that revs up the sex drive? The increase in sexual activity at at the end of December harks back to Saturnalia, a pagan holiday when people feasted on boar flesh and indulged in a lot of prehibernatory sex. Disapproving early Christians coopted the sexfest and turned it into the celebration of Jesus’s birth. “Why either/or?” ask modern day revelers, and now many both celebrate the baby Jesus and also enjoy conceiving (or preventing the conception of) their own babies. It’s unsurprising that people have more sex during the weeklong holiday: we have time to relax, drink, and socialize more. And not everyone wears Trojans — the birthrate in the United States peaks in the summer and in September, nine months after the winter bacchanalia.

Even more interesting, there may be a biological reason why people’s sex lives heat up as the seasons cool down. In BLONDES I describe the connection between hormone levels and waning daylight hours in autumn. And we’re not alone: other animals in the northern hemisphere also have their rutting season in the late fall — including reindeer.

Where in the world to have a fling

Posted in news by jenapincott on December 4, 2008

90937I devoted a page or so of BLONDES to places in the world where people are most promiscuous, based on the findings of the International Sexuality Description Project (IDSP). Now here’s an addendum — a new study, also by the IDSP, that has found links between national character and sexuality based on surveys taken by more than 13,000 people in 46 nations. The researchers found that nations vary in character — for instance, some have more “extroverted” and “neurotic” cultures than others.

Unsurprisingly, extroversion is linked with promiscuity, and men and women in “introverted” nations — South Korea, Hong Kong, Japan, and Ethiopia — reported less promiscuity and desire for flings. Women who scored highest on both extroversion and promiscuity tend to be from Europe — in particular, Serbia, Croatia, Switzerland, and Austria. Extroverts were also more likely to “poach” mates, i.e. steal another person’s partner.

Neuroticism (defined by anxiety and high stress) was another factor, and countries with the highest scores on this count — Japan, South Korea, Taiwan, and Hong Kong — had fewer people reporting or desiring flings than those in the relatively laidback countries of Finland, Slovenia, Croatia, and New Zealand. However, there’s a notable exception to the rule: North American women who scored high in neuroticism were more likely to be promiscuous.

As the researchers themselves point out, there are limitations to the study. For one, some nations might be more truthful in surveys than others, or have different conceptions of promiscuity and short-term relationships. Perhaps “conscientious, neurotic, introverted” nations such as Japan are actually more promiscuous than one might imagine….

The more sex a woman has with her partner, the more committed

Posted in news by jenapincott on November 15, 2008

42-15225272The more sex a woman has with her partner, the less attracted she is to other men. That’s the upshot of a study by medical psychologists Ursula Hess, Stuart Brody, and their colleagues, who asked female subjects to report the details of their sex lives and rate the facial attractiveness of twenty-four men. Sexually sated women gave hot guys significantly lower ratings than did women who weren’t having as much sex. Simply put: the more sex women recently had with their partners, the less attracted they were to hunky alternatives. It’s as if biology blinds them to other opportunities.

Several factors may be at play here — and hormones are implicated. As I describe in BLONDES, the hormone prolactin, released after orgasm, makes a person feel sated, at least for awhile (two days, according to some studies, and up to a week according to others). The hormone oxytocin — released when touching, caressing, kissing, and orgasming — makes a woman feel more attached to and trusting of her current partner, even if he’s just a fling (the study didn’t measure relationship strength). Naturally, the more attached a woman feels, the less likely she’ll be on the lookout for another beau. Or it just might be love. A separate study led by evolutionary psychologist John Maner also found that women (and men) in love are automatically less likely to pay attention to the faces of good-looking strangers.

(Of course the whole phenomenon could be a virtuous cycle: the more committed, the more sex — and the more sex, the more committed.)

As a separate and interesting side note, researchers in the sex study also found that depressed women — even those with partners — masturbate more, which the researchers think may either be self-soothing or actually exacerbate depressive symptoms. That, or it just might be that these women are down because they haven’t found the right partners. Perhaps they’ve blinded themselves to other opportunities.

I’d like to know if the same is true for men.

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