Science of Love, Sex, and Babies

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 hypochondriacs prefer macho men?

Posted in news by jenapincott on January 8, 2010

Evolutionary psychologists tell us that one of the reasons why women find masculinity attractive is that high testosterone is a sign of a strong immune system. A strong immune system, in turn, in a sign of good genes and childhood development (testosterone is an immunosuppressant and only men with good genes can overcome its drawbacks). These strong square-jawed macho men aren’t necessarily good dads: they’re more likely to be uncooperative, combative, and aggressive. But they may offer good genetic material for your kids, depending on the circumstances.

So how do you prove that women equate masculinity with good genes and healthy immune systems (subconsciously, at least)? An indirect approach was taken by Lisa DeBruine and her colleagues at the Face Research Lab at the University of Aberdeen. (The Lab conducts many fascinating studies on attraction, some of which I reference in BLONDES.)

In this new study, DeBruine recruited 345 women of all ages to rate faces. The faces were digitally altered, and ranged from very masculine to very feminine. Participants also completed a test called the Three-Domain Disgust scale, designed to measure moral disgust (deceiving a friend), sexual disgust (hearing strangers have sex), and pathogen disgust (stepping on poop).

Turns out that women’s preference for masculinity in male faces was correlated with disgust sensitivity to pathogens, but not in the moral and sexual domains. (Yes, hypochondriacs do prefer macho men!) DeBruine speculates that in certain situations, such as disease-ridden environments, women are wired to prefer high-testosterone males. The benefits of their good immune system genes are worth the tradeoff.

The testosterone-means-good-genes theory, anyway, may explain why women in disease-ridden environments are likelier to choose macho guys. Explains DeBruine et al.:

Because a partner’s heritable health is of greater value when pathogens are a greater concern, concern about pathogens is likely to also be a factor that contributes to the resolution of this tradeoff. Cross-cultural differences in mate preferences and mating systems vary consistently with differences in pathogen prevalence. When people from 29 different cultures were asked to rank a series of attributes based on how important they would be in a mate, people in areas with a high prevalence of pathogens ranked physical attractiveness higher than people in areas with a relatively low prevalence of pathogens did. Also consistent with these
findings, rural Jamaican women prefer masculinity more than British women do…

So do hypochondriacs, fearful of disease, marry more macho men (e.g. self-professed hypochondriac Susie Essman and her new husband?) As environments become more sterile, will we prefer men with softer, sweeter faces and personalities? Or will the next swine flu outbreak inspire us to pursue pigs?

Hormones in 20 seconds or less

Posted in news by jenapincott on May 16, 2009

The_Notebook_Limited_Edition_DVD-Contest-Ryan_Gosling-Rachel_McAdamsWithin 20 seconds of encountering a beautiful woman, men have been shown to have a surge of two hormones: testosterone and cortisol. This makes good sense, evolutionarily speaking. As I describe in BLONDES, hormones mirror the subconscious mind. Testosterone promotes assertiveness and reflects increased sexual desire. Cortisol focuses motivation. Women are the choosier of the sexes, which means — generally, of course — that the onus is on men to flaunt and flatter or take other action to attract the woman.

But what do women do when they see an attractive man?

The same thing. Far from being passive observers, women also experience a hormonal riot within seconds of seeing a hot guy. This is true even if the man is an actor in a film, as indicated in a new study led by neuroscientist Hassan Lopez at Skidmore College. Lopez and his team showed 120 women one of four 20-minute videos, each with a different scenario: 1.) an attractive man courting a woman (a clip from The Notebook starring Ryan Gosling) exhibiting a dominant social presence, risk-taking, kindness to children, faithfulness, confidence, and humor 2.) a nature documentary about caves; 3.) an unattractive older man (Jack Nicholson) courting a woman 4.) an attractive woman (Cameron Diaz) with no man present. Saliva samples were taken right before and after each viewing.

Of all four groups, only the women watching the hot, desirable, “high mate value” guy trying to seduce a woman had a surge of testosterone and cortisol. The higher the hormones, the stronger the romantic/sexual interest the women reported. (Interestingly, women on birth control pills only experienced a cortisol surge, not testosterone, apparently because the pill suppresses the hormone. Naturally-cycling women also reported a greater willingness to engage in sexual activity and enter a relationship with the attractive man. This may be due to stronger hormonal surges in women who aren’t on the Pill or the fact that more Pill-takers are already taken.)

The study reminds us that hormones help both sexes focus and flirt more effectively, and a surge at the sight of an attractive prospect may change our moods in an instant. But what threshold must be met to trigger such a surge? Do women with higher baseline testosterone and cortisol levels respond faster and get turned on easier? Are high testosterone men more effective in raising women’s hormones? Could taking the Pill really decrease your natural attraction to handsome strangers? And when two people mutually elevate each other’s hormones within seconds, is that considered love at first sight — or just lust?

Why Tiger Woods lost

Posted in news by jenapincott on February 26, 2009

tiger-woods-son-240x320 For the past eight months before today’s loss in the World Golf Championships- Accenture Match, champion Tiger Woods had been recovering from a knee injury. He told several reporters that he enjoyed the time spent at home. More than ever before, he got to hang out with his pregnant wife, Elin, and their two-year-old daughter Sam Alexis. Earlier this month Elin gave birth to a son, Charlie Axel.

Tiger’s ignominious loss today could be attributed to the possibility that he’s out of practice. Maybe his knee was still acting up (although he said it felt fine). Perhaps he hasn’t been getting enough sleep, or he had an off day. But there’s another theory: it’s hormonal. It could well be that Tiger’s testosterone levels are down.

That would certainly be the case if Tiger Woods is like the many loving husbands and dads participating in studies by medical anthropologist Peter Gray at the University of Nevada. As discussed in BLONDES, studies have shown that men’s testosterone levels take a nosedive when they’re in serious, committed relationships. Spending time at home in the comfort of a loving relationship can do the trick.

When a child is born, a dad’s circulating testosterone may be at an all-time low. Gray and his colleagues have seen this effect in dads all over the world. Lower testosterone levels make a man less aggressive, less focused and competitive — and more agreeable and responsive. Even holding a baby doll can make expectant father’s testosterone levels plummet. If Tiger’s T-levels are lower, it’s good news for his newborn son but bad news for his game. From an evolutionary perspective, newborn Charlie Axel is manipulating Tiger’s hormone levels so he’ll be a better dad.

Of course, little does Mother Nature know that when Dad’s a professional athlete, it’s best to leave his hormones well enough alone.

Poor little down-and-out T

Posted in news by jenapincott on October 30, 2008

I devote a chunk of BLONDES to the Environmental Security Hypothesis (ESH), which says that in tough times men prefer women who are slightly older, heavier, taller, more mature-looking, and less curvaceous.  In good times, men go back to their default:  younger, shorter, lighter, curvier, big-eyed, feminine-looking damsels.  It’s as if men unconsciously seek what is practical when the going gets tough — strong and robust women.   (FYI – women’s preferences in men don’t fluctuate under adverse conditions.) The ESH has been supported in a variety of studies, including one with  ravenous college students, another with men in a “crisis” mind-set, and a famous one that tracks the dimensions of Playboy Playmates of the Year over several decades of economic ups and downs.

What exactly drives men into “Environmental Security” mode?  Low blood sugar levels are one possibility, as noted in the study of hungry men.  Low testosterone (T) levels are another, and men’s T levels fluctuate all the time. They’re known to surge when men win a game or have a confrontation and dip when they’re feeling down. A new study led by Lisa Welling at the Face Research Lab found that when men’s T levels are high, they report stronger attraction to femininity in women’s faces.  When levels are relatively low, men report a weaker preference for femininity.  Put another way:  High testosterone loves high estrogen.  Low testosterone might not mind lower estrogen.

The results inspire some prurient speculation.  Do guys who are generally low in T have a preference for “more masculine” women? In the current economic environment, are testosterone-deficient Wall Street traders trading in their trophy wives for sugar mamas? Are curvy, girly strippers making less than their heavier, hipless dominatrix colleagues?

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