Less sex for new fathers linked to drop in their testosterone levels

Researchers have found evidence - if evidence were needed - that men have less sex after becoming a father for the first time.

A study of more than 400 young men in the Philippines found that their sex lives declined significantly when they had their first child. The fall in sexual activity was associated with the men's testosterone levels, which are known to fall when men start families, but the latest research shows that the greater the fall in testosterone, the less sex men reported.

Lee Gettler, an anthropologist at the University of Notre Dame in the US state of Indiana, gathered medical and lifestyle information on the men from the ages of 21 to 26 and found there were physiological and behavioural changes as some of them married and had children.

When men got married their testosterone levels fell, and declined even further when they had their first child. That led to the question of whether falling testosterone might impact on their sex lives.

"I didn't think that testosterone would be linked to men's sexual behaviour, but when we tested it we found that as men transitioned to fatherhood, the more their testosterone declined the less frequently they reported having sex with their partner," Gettler said.

The impact on men's sex lives was not linked to the amount of time and energy they invested in childcare, he said.