Men are biologically wired to care for their babies, as the act of childcare reduces testosterone levels by 34%, a recent study indicates.
This may be nature’s way of encouraging a more caring side in men, to ensure that dads stick around to bring up their children, the study suggests.
The research reveals that high testosterone levels, commonly associated with dominant and aggressive behaviour, are more likely to secure a partner and produce children, but after birth these levels drop, especially in the period immediately after bringing a new baby home. Although testosterone levels slowly rise after this, they don’t return to pre-fatherhood levels.
“Raising human offspring is such an effort that it is co-operative by necessity, and our study shows that human fathers are biologically wired to help with the job,” said Christopher Kuzawa, co-author of the study published in the journal Proceedings of the National Academy of Sciences.
“To see dramatic changes in response to family life is intriguing. The observations could make some evolutionary sense if we accept the idea that men with lower testosterone levels are more likely to be monogamous with their partner and care for children,” said Dr Allen Pacey, a sexual health expert at Sheffield University. “Testosterone is the key hormone that defines male physiology,” he added.
“It’s not the case that men with lower testosterone are simply more likely to become fathers. On the contrary, the men who started with high testosterone were more likely to become father, but once they did, their testosterone went down substantially,” explained Lee Gettler, a doctoral student who assisted with the study.
The study looked at 624 men in their 20s from the Philippines, and followed them for four and a half years, reports the Telegraph.