Want to hyphenate your last name to include your wife's? Is "Three Men and a Baby" your favorite movie? If you are a man, these and other distinguishing characteristics probably mean you have lower testosterone.

It has long been known that among humans (and some other species as well), males who over-help their female mates with offspring have lower testosterone levels than the more aggressive among their gender.

But to find out why, it might mean looking beyond the nuclear family. Not only spouses, but also other relatives, good friends, colleagues, neighbors and fellow church members can play a role, suggest Lee T. Gettler, assistant professor of anthropology and director of the Notre Dame's Hormones, Health, and Human Behavior Laboratory, and Rahul C. Oka, Ford Family Assistant Professor of Anthropology, in an article forthcoming in the journal Hormones and Behavior.

The new study focuses on a large, representative sample of aging U.S. men and the ways their testosterone varies when they have emotionally supportive relationships.

"Compared to other U.S. men, fathers and married men often have lower testosterone," Gettler said. "We think this helps them be more nurturing. We are the first to show that this also occurs with other social relationships. Our results show that when older men have emotionally supportive relationships with their siblings, friends, neighbors and coworkers, they also have lower testosterone."

According to Gettler, "We know that men and women with social support have much better health, overall, while testosterone affects risks for depression, cardiovascular disease, obesity and some cancers. We hope our findings, connecting these two areas, help stimulate new conversations about social support, biology and well-being.

"Most of us have probably seen the TV commercials promoting testosterone as a remedy for symptoms of aging or 'manopause.' Our findings suggest that the social side effects of these testosterone supplements in older men should be carefully studied. While testosterone does go down with age, the potential social benefits that can accompany lower testosterone suggest it is not all doom and gloom."