Testosterone Dives When Kids Show Up

All men experience a long slow and one-way drop in testosterone starting sometime in the twenties, but now it seems that behavior also plays a role, and one behavior that seriously turns off the testosterone is nurturing children. Researchers at Northwestern University who studied a group of 624 men aged 21.5 to 26 years old for 4.5 years found that the men who started with high testosterone were more likely to become fathers, but once they did, their testosterone went down substantially. The findings suggest that this is especially true for fathers who become the most involved with child care. A Northwestern news release reports that the effect is consistent with what is observed in many other species in which males help take care of dependent offspring. Testosterone boosts behaviors and other traits that help a male compete for a mate. After they succeed and become fathers, “mating-related” activities may conflict with the responsibilities of fatherhood, making it advantageous for the body to reduce production of the hormone.

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