New Study Finds Smaller Testicles Make for Better Dads

As if guys didn't have enough size-related neuroses going on down there, a new study suggests that testicle-size actually plays an important role in what kind of dad a man will be — and the smaller, the better, it seems.

Anthropologists at Emory University took the time to measure the brains and testicles of 70 guys, finding that men with smaller testes were way more likely to handle their children's nappy-changes, bath-time, feeding, and general care-giving.

The implications? Pretty, er, big, it turns out.

“It’s an important question,” one of the anthropologists said. “Because previous studies have shown that children with more involved fathers have better social, psychological and educational outcomes.”

Other research has suggested that, when it comes to animals, those with the largest nuts tended to mate with the most partners. And higher testosterone levels are indeed found in guys with less interest in raising children. So it stands to reason that there might be a trade-off, evolutionarily speaking, between investing effort in creating vs. in raising children.

The researchers had the dudes' partners fill out questionnaires about how involved their men were in the child-rearing. Those with smaller balls got the highest scores. The study also found that the brain scans of men with smaller testes showed them having stronger reactions to seeing photographs of their own children than the brains of guys with bigger testes.

But the anthropologists were quick to point out that this doesn't mean the well-endowed get to be slacker parents.

“The fact that we found this variance suggests personal choice,” the researcher said. “Even though some men may be built differently, perhaps they are willing themselves to be more hands-on fathers. It might be more challenging for some men to do these kinds of caregiving activities, but that by no means excuses them.”

They also cautioned against jumping to conclusions too quickly — there's always the causation/correlation issue.

“We’re assuming that testes size drives how involved the fathers are,” Rilling says, “but it could also be that when men become more involved as caregivers, their testes shrink. Environmental influences can change biology. We know, for instance, that testosterone levels go down when men become involved fathers."

Looks like this guy won't be going on diaper-duty any time soon.

Image: Syda Productions/Fotolia