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Physicist, Startup Founder, Blogger, Dad

Monday, September 12, 2011

Fatherhood suppresses testosterone

No wonder I feel so wimpy :-(

NYTimes: ... Testosterone was measured when the men were 21 and single, and again nearly five years later. Although testosterone naturally decreases with age, men who became fathers showed much greater declines, more than double the childless men.

And men who spent more than three hours a day caring for children — playing, feeding, bathing, toileting, reading or dressing them — had the lowest testosterone.

Below is the abstract from the original paper (PNAS).

In species in which males care for young, testosterone (T) is often high during mating periods but then declines to allow for caregiving of resulting offspring. This model may apply to human males, but past human studies of T and fatherhood have been cross-sectional, making it unclear whether fatherhood suppresses T or if men with lower T are more likely to become fathers. Here, we use a large representative study in the Philippines (n = 624) to show that among single nonfathers at baseline (2005) (21.5 ± 0.3 y), men with high waking T were more likely to become partnered fathers by the time of follow-up 4.5 y later (P < 0.05). Men who became partnered fathers then experienced large declines in waking (median: −26%) and evening (median: −34%) T, which were significantly greater than declines in single nonfathers (P < 0.001). Consistent with the hypothesis that child interaction suppresses T, fathers reporting 3 h or more of daily childcare had lower T at follow-up compared with fathers not involved in care (P < 0.05). Using longitudinal data, these findings show that T and reproductive strategy have bidirectional relationships in human males, with high T predicting subsequent mating success but then declining rapidly after men become fathers. Our findings suggest that T mediates tradeoffs between mating and parenting in humans, as seen in other species in which fathers care for young. They also highlight one likely explanation for previously observed health disparities between partnered fathers and single men.

9 comments:

Christopher Chang said...

Nature probably doesn't want you to kill and eat your own children...

Nick Westgate said...

Yeah, there's probably good reason for it, but it still sucks. Does anyone have access to the article? What are the health disparities?

Cheers,
Nick.

Lisa said...

Sheesh Steve. if that’s true you are probably a eunuch by now.

KenC said...

The Lisa comment was from me. That’s my cousin and she failed to sign off on my computer. Amazingly--I agree with her comment ;)

Sabine Hossenfelder said...

Prolactin suppresses estrogen. That is to say, maybe they should look at the mothers rather than the children for cause. 

lovehorrorfilms said...

Perhaps low testosterone men are more likely to start a family and raise children, while high testosterone men simply sleep around producing illegitimate kids.  

Ene Dene said...

Hmmm, I doubt it:
http://www.acf.hhs.gov/programs/cb/pubs/cm08/figure3_6.htm
http://thenononsenseman.com/Media/ChildAbuseByPerp_ACF2009.pdf

Oakland Peters said...

Testosterone is much over-valued in the modern day. It is associated with increased levels of aggression and intensity -- various studies have shown a strong correlation between elevated long-term testosterone levels and criminality as well as diminished interpersonal relationships and academic performance.

The diminished testosterone associated with fatherhood is just evolution's way of telling you that you can calm down -- because you have children, you are succeeding in the race of life.

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