Photo: NY Daily News
Photo: NY Daily News

Often, a couple’s sex life plummets after the birth of a new baby as new mothers often worry that they are no longer as attractive in the eyes of their lover.

However, a new study suggests that parenthood not only affects the biology of mothers, but also of fathers.

During the first year after a birth of a baby, fathers go through a drop of testosterone of around one third, and those who assist with childcare for at least three hours a day see a further drop of 20%.

The new fathers who took part in the research also reported having less sex.

Researchers believe that the ‘sensitising’ effect is influenced by the psychological and cultural impulse to be protective over the newborn, and even adoptive fathers have the same impact.

Men with less testosterone are likely to be less aggressive and more caring. Previous studies have also shown that men with high testosterone levels feel less sympathy or need to respond to a crying baby.

To all new moms out there who feel anxious because your partners do not want to have sex, this study shows that you need not worry about them straying after the birth of a child. It’s just that they are naturally programmed to focus on looking after their baby at the expense of their sex drive.

The largest study of its kind, Dr. Lee Gettler of Notre Dame investigated on how the biology of new fathers change after the birth of their children.

“It’s not just mothers who go through pregnancy and birth and it’s not just mothers who biologically respond to parenthood. Fathers can biologically respond to the needs of children too,” he said.

“We found that men who became new fathers had a decline of testosterone of between 33-34 per cent. Men who were most involved in the day to day hands on childcare had the lowest testosterone levels.

“If you think about fathers in other mammalian species they don’t really help taking care of the children.

“So it seems that natural selection has stepped up men’s hormone system to respond to the needs of their offspring.

“Our species has evolved paternal instincts which are somewhat unique to our species compared with our closest relatives.”

Dr. Gettler studied more than 400 men in the Philippines. He tested their testosterone levels when they were single, aged 21 and then retested them at 26 when many of them had become new fathers.

The researchers say they are unclear why fatherhood would cause couples to have less sex having considered controlled factors which could impact intimacy, such as having a young child sleeping in the same room, the parents being more tired or having less time because of childcare.

They also do not believe that the fall in testosterone is linked to a fall in libido, although it may be possible that women find their new partner less attractive because of the hormonal change, the researchers suggest.

It may also improve the stability of the relationship as previous studies have shown that men with higher testosterone are more likely to have marital problems and to be divorced.

Those who claimed that they have sex with the partner less than once a week had the lowest testosterone levels.

If you’re married with newborns, care to dish on your sex lives? 😉


Carmen Chong
YouTube-obsessed and a beauty junkie at heart. Find her on Instagram: @carthemen