I’m amazed that they actually did this work [ Proc. Natl. Acad. Sci. vol. 110 pp. 15746 - 15751 '13 ] but they did. From Atlanta Georgia, the home of the Southern Gentleman. You do have to wonder what sort of wimps would permit this type of work. 70 such individuals were found, still cohabiting with the mother. Clearly a skewed distribution as 65/70 were actually married. No mention of any effect of the sex of the offspring on what they found.
Here’s what they did
Testosterone levels and testicular volume predicted how much parenting a male actually did (based on self-reports from the two parents). Functional MRI on viewing a picture of the offspring also predicted the degree of male parenting.
So which way do you think it went?
The bigger the testicles and the higher the testosterone, the less parenting the father did. Similarly the less activation of one area of the brain in response to a picture of their chile, the less parenting.
So ladies, you may get a macho dude for a mate, but don’t expect much help.