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Fatherhood decreases testosterone, may create nurturing fathers
September 12th, 2011
04:52 PM ET

Fatherhood decreases testosterone, may create nurturing fathers

Let's face it - throughout most of human history, stereotypes have dictated that women are more adept caregivers for children than men. Child-rearing is assumed to be in the female domain, while providing is considered inherently male. A large study of testosterone levels in men is turning that assumption on its head, suggesting that fatherhood actually lowers levels of the hormone once men become fathers, re-wiring them to be more nurturing.

"This suggests that a lot of stereotypes about men and child-rearing, maybe we need to rethink them a little bit," said Chris Kuzawa, associate professor of anthropology at Northwestern University, and co-author of the study. "It seems like it's part of our biological make-up to shift into the role of caregiver once it's required of us."

That shift occurs as a man becomes a father, according to the study, just published in the journal, Proceedings of the National Academy of Science. Several hundred Filipino men participating in the Cebu Longitudinal Health and Nutrition Survey had their testosterone levels measured in their early twenties, when they were single and at their most virile. Their testosterone was measured again about five years later, once they had married and had children.

It turns out that testosterone levels dipped by one-third when a man became an actively involved father (spending three or more hours a day interacting with their child) and that dip was even more remarkable - about 50% - during the first month after his child was born, according to Kuzawa.

The more time a father spent caring for his child, the lower his testosterone levels.

"When fathers make a choice to be actively involved with their children, their biology responds," said Lee Gettler, lead author of the study and graduate student in the department of anthropology at Northwestern University. "It reinforces that choice and may allow the father to maybe be more focused on that role."

Since men in the study were tested at baseline - before they became fathers - and had high levels of testosterone, the study suggests that it is not men with low testosterone levels who are more likely to become fathers. Rather, it is fatherhood that leads testosterone to go down.

"This certainly adds a layer of complexity to our stereotypical roles," said Gettler. "It's not just mothers that have the innate ability to be caregivers, but men have that built-in capacity biologically as well."

And the implications of the study may extend far beyond proving that men are biologically adept caregivers. Low testosterone is associated with lower risks of prostate and testicular cancer. Future studies may prove that men who are fathers reap benefits, other than enhanced relationships with their children, from lowered testosterone levels.


soundoff (13 Responses)
  1. Andy

    Nonesense. Has NOTHING to do with being a father, has EVERYTHING to do with getting older. Take that same father at age 25 who had a kid at age 20...his testosterone levels will not drop...but at age 35, will drop compared to 25. Also take into account that most fathers do not work out as much as they did when they were single (if they worked out then). That too plays a role in testosterone as do eathing habits which may change once a man becomes a father...
    Please, use legit science to make conclusions, not fluff.

    September 13, 2011 at 09:34 | Report abuse | Reply
    • Robert

      Andy I agree!... This is why in general I believe a majority of our educators in this country, although very "book smart", lack a lot of common sense. Andy you mentioned the age issue which is 100% true, and let us not forget that when you get married or have a kid you have LESS TIME to do things that keep testosterone levels naturally high like working out, getting 8 hours of sleep, and not having to sit at a desk all day for work!.... interesting that 1 month after a kid was born testosterone levels fell by 50%...well what happens in that first month normally?.... YOU GET NO SLEEP!..... but these researchers try to draw a conclusion based on limited evidence that simply having a kid causes testosterone to plumit..... the truth is that it is OTHER factors like age, lack of sleep, and life-style changes. Well-educated IDIOTS our educating our children - They fail to see the bigger picture of things.

      September 13, 2011 at 10:10 | Report abuse |
    • MikeGCNY

      One major problem with this article that may or may not be seen in the study. Where is the control group of men who don't become fathers? How much of a drop in testosterone levels is there for men in the same 5 year age difference?

      September 13, 2011 at 12:38 | Report abuse |
    • Chartreuxe

      One must presume that there were controls in this study: men who were not fathers but who were of similar age as the dads. These conclusions would not otherwise have been drawn regarding fatherhood and testosterone.

      September 13, 2011 at 12:47 | Report abuse |
    • Jimmy

      Actually, testosterone peaks in your mid 30's. It's just that your estrogen levels go up as well which is why a 20 year old is more "spry".

      September 13, 2011 at 16:20 | Report abuse |
  2. Mo

    So What? Men become lazy and don't make an effort to keep up with their manly duties. Its easier to sit on a couch with your kid and eat fat pills. Get out and so some manual labor or join a gym. I love my kid and spend time with her but also find time to do my manly stuff like gym, moutain biking and crossfit.

    September 13, 2011 at 10:35 | Report abuse | Reply
  3. Lets Produce

    ." Low testosterone is associated with lower risks of prostate and testicular cancer." Current research tells a different story. Prostate cancer is now linked with low testosterone levels, not normal testosterone levels. It's interesting to note that the vast majority of men who get prostate cancer do so at a time when their testosterone levels are much lower than when they were younger. My doctor put me on testosterone replacement 10 months ago. I was five months shy of my sixtieth birthday. Since my father died from prostate cancer, I didn't make this decision lightly. All the current research points to low testosterone being a risk factor for prostate cancer which is the exact opposite of what was once believed. Low testosterone also puts men at increased risk for heart disease.

    September 13, 2011 at 10:44 | Report abuse | Reply
  4. DONELL THOMAS BROWN

    keep in mind The pituitary gland controls the level of testosterone in the body so how true is this study ?

    September 13, 2011 at 11:08 | Report abuse | Reply
  5. TJ

    This is a classic example of someone assuming correlation means causation. This is the silliest, pseudo-scientific, mumbo-jumbo I've read in a while. Do better CNN.

    September 13, 2011 at 14:21 | Report abuse | Reply
  6. BKK

    what about receding hair the older we get? isn't that mostly due to high testo... and Propecia like drugs lower it? guess other chems are there too.

    September 13, 2011 at 19:02 | Report abuse | Reply
  7. slogreport

    this is not a good thing because men will not be able to slog at slogreport.com

    September 13, 2011 at 22:47 | Report abuse | Reply
  8. Steve

    Male hypogonadism is the medical phrase used to describe men with severe testosterone deficiency. The degree of severity of the condition can vary from individual to individual, but there is universal similarity of symptoms in testosterone deficient males – these include fatigue, lethargy, mood changes, ill temper, sexual dysfunction, poor erectile function, loss of sexual interest, diminished muscle strength, osteoporosis and anaemia.

    For more details go to: http://www.bio-identical-testosterone.com/bio-identical-testosterone-content/men-and-testosterone/causes-of-testosterone-deficiency-in-men/

    February 10, 2012 at 01:24 | Report abuse | Reply
  9. Taisha Aamot

    Whether you're expecting your first child or your kids are grown and on their own, being a dad is a new experience. When my wife was pregnant, we decided to have a homebirth. We hired a doula and two midwives. I won't tell you how much it cost. According to them and other experts, labor was going to last 10-12 hours. My son had other plans. My wife's labor was so short that the only other person in the room when he was born was – guess who? – me. After nine months of preparing to support my wife in the birth of my first child, there I was, with no medical training, serving as midwife, doula, and doctor. I fought off the strong desire to run out of the room as fast as possible. When I caught Joaquin, I experienced pure exhilaration and love. ,-

    Most recent short article on our own website
    <http://www.caramoanpackage.com

    May 6, 2013 at 02:40 | Report abuse | Reply

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