UNLV Magazine

Spring 2008

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Family grows, hormone slows

Research on testosterone in dads looks beyond the easy explanations

by Matt Jacob

Last year, anthropology professor Peter Gray published a pair of studies concluding that testosterone levels in men drop significantly after marriage and fatherhood. I must admit my first reaction was to scoff.

Gee, what's next, a study that confirms the sky is blue? That water is wet? That wives are prone to nag and husbands have a tendency to be lazy?

Gray, a 34-year-old married father of two young girls, understands such mockery. "Well, duh!" he says some might react. "This is so patently obvious. Obviously, something is happening within a man's body."

Of course accepting "Duh!" and moving on wasn't good enough for Gray, who has been teaching at UNLV since fall 2005. It's in his anthropologist's DNA to look beyond the obvious, to explore the science in an effort to explain the reality and expand our understanding of it. "Ask anyone who's been married recently or who has become a parent recently if they feel like their life is organized any differently," Gray says. "Often you'll get an answer of ‘Yes! I sleep less, my emotional relationships with my partner are changed,' etc. But what's happening in our bodies that's reflective of those changes? One of the first physiological actions to look at is that related to testosterone levels."

Because his is a field that studies cross-cultural similarities and differences, it was a no-brainer for Gray to travel abroad with colleagues to measure the physiological impact of marriage and fatherhood in two nontraditional societies.

The first study, conducted in summer 2004 in northern Kenya, involved surveying and collecting saliva samples from 203 single and married males of the Ariaal tribe. The results were by and large predictable: Those who were single and childless had higher levels of testosterone than those who were monogamously married with offspring. But, unlike in our society, Ariaal fathers have almost no involvement in childrearing. Their main task is to accumulate and maintain wealth — two masculine pursuits that do not correlate with lower testosterone levels.

Another of Gray's findings bucked conventional wisdom: Those who had multiple wives — a common practice among the Ariaal tribe — had even lower testosterone levels than their monogamous counterparts. "We thought that [having multiple wives] would be associated with higher testosterone levels from the standpoint that you might still be looking [for an additional wife] or you might have to guard them to some degree. That was not the case."

Two years after the study in Kenya, Gray and his colleagues went to Jamaica and surveyed 43 men who submitted saliva, urine, and fingerprick bloodspot samples to measure fluctuations in multiple hormones, including testosterone. Once again, the findings between single and married men were expected: those who were single had higher levels of key male hormones than those in committed relationships. But the one oddity in this study stemmed from a comparison between dads who were actively living with their families and absentee fathers who only visited. Surprisingly, the latter group had lower testosterone levels, even though they weren't as involved in the daily upbringing of their children.

Although nothing in his research explained this particular quirk, Gray theorizes it has to do with the fact visiting fathers aren't prone to the same stress-inducing — and hence testosterone-increasing — issues that at-home dads deal with.

As for the overall impact of his recent work, Gray says there are several inferences that can be drawn and long-held theories confirmed — notably, that having a wife improves a man's overall health. Past research shows that married men around the world live longer and experience fewer illnesses. "Well, why is that?" Gray wants to know. "Is it just that you eat better? Or is there something happening in the physiology of married men that's helping to account for that, such as lower testosterone levels associated with long-term relationships like marriage? So this research may start to account for the healthrelated benefits of social relationships that people like epidemiologists have long noted but haven't necessarily connected to physiological shifts."

In other words, it would be wise for those of us married-with-children types to think twice before blurting out the cliché "My wife and kids are killing me."