Just as the size of a seed can impact the fruit it generates, researchers are now trying to understand if the size of a man’s testicles can be an indicator of how well he’ll do as a father.
A new study published in the Proceedings of the National Academy of Sciences found men with smaller testes have healthier, more involved relationships with their children.
Using an MRI, researchers measured the true size, or volume, of the testicles of 70 men. An MRI was also used to record brain levels as the participants looked at photographs of their children.
Additionally, the men completed questionnaires about their personal lives and their level of involvement in raising their children.
Those with smaller or lesser volume testicles were found to be the more nurturing type, something earlier research had similarly determined about men with higher testosterone levels.
“Men with smaller testes have healthier
relationships with their children.”
The MRI results showed men of lesser testicular volume experienced more brain activity in the region associated with nurturing and those men responded more fiercely when shown photos of their children expressing emotion.
Study co-author James Rilling, of Emory University, said it’s difficult to determination which trait came first.
“We know in modern Western societies children with more involved fathers have better developmental outcomes,” he said. “It could be that as men become more involved in care giving, (then) the testes shrink.”
Source: pnas.org. Photo source: turner.com.