Becoming a dad has a definite sexual downside, research shows. Fatherhood causes a drop in testosterone, according to the study, which was reported in The New York Times.

Researchers measured the testosterone levels of single men at the age of 21, and again some years later. They reported that when men fathered a child, their testosterone levels declined at a faster rate than did the testosterone levels of childless men.

"Sex ruts" are very common for new dads, says Ian Kerner, Ph.D. "Lower testosterone levels can be evolution's way of protecting the baby and even helping to ward off infidelity."

Sarah Nasserzadeh, Ph. D., co-author of The Orgasm Answer Guide, agrees, explaining that testosterone can be linked to high sexual activity and risk-taking behavior in guys. "From an evolutionary standpoint, it can be argued that testosterone drops since a father is needed to be around for his child," she says.

It can't all be blamed on fatherhood. Dads with a lower testosterone level may have other lifestyle habits that contribute to a less than satisfactory sex life.

"They may have metabolic syndrome and be overweight," says Elizabeth Kavaler, MD, a New York City urologist. "They don't want to go to the gym, they work too much, they are in jobs that are tenuous and so they are under a lot of stress."

Since a low testosterone level in a man can be due to lifestyle factors as well as becoming a dad, getting back on track and enjoying sex with a partner again often means making some general changes.

To get your sex life back on track, Kerner says, "It is important for new parents to reprioritize and put intimacy at the top of the list.  Happy kids have happy parents, and for parents to be happy, they need to feel a connection with each other."

New dads should:

1. Work with your partner to rekindle your sex life, making a conscious effort to find time for intimacy.

2. Make sure to take care of basic needs, such as eating right, sleeping enough (or as much as one possibly can with a new baby), and getting exercise, says Nasserzadeh. Try to avoid stress as much as possible.

3. Take control over whatever you can. In the first months after a new baby arrives, this may seem like basically nothing. But try to establish a schedule for having sex - even if it's at odd times of the day or night, when your baby is napping.

4. If you've got "complicating factors," such as another child (who's not sleeping the same hours as a newborn), try to make some time away from home with your partner. Even if it's just a dinner and a movie out, getting in some snuggling and intimacy can go a long way in making the two of you feel close again.

5. Get tested. If your testosterone drops to a certain level, your doctor may prescribe medications that can help.


Belluck, Pam. "In study, fatherhood leads to a drop in testosterone." 12 September 2011. The New York Times.