My opinion: At first I thought this study may have correlated with hormones, but as it turns out, it doesn't. Testicular size doesn't appear to affect the amount of testosterone and semen volume. If it did, then perhaps these particular fathers would have acted, in some regards, more involved like mothers because of a higher estrogen to testosterone ratio. But it is more likely a matter of evolutionary factors, that is, men who have smaller testicles may not mate as much, and therefore may have more time to help raise children. It would be interesting to see if these fathers are having fewer children than those with bigger "materials." If so, then the fathers may be more involved simply because they don't have as many kids on their hands, rather than spending their time trying to mate. Any other thoughts on this bizarre study? Feel free to comment.
Study: Smaller testicles, more-involved dads?
updated 5:23 PM EDT, Mon September 9, 2013
- Study suggests that dads with smaller testicles are more nurturing
- Research doesn't claim size of a man's genitals determines how good of a dad he'll be
- Previous studies suggested less testosterone leads to less mating, more parenting
Editor's note: CNN's Josh Levs covers a wide range of topics and offers his personal take on fatherhood. He describes parenthood as part of the ultimate dream in his TEDx talk, "Breaking the System to Achieve the Impossible." Follow him on Twitter and Facebook.(CNN) -- Oh, boy.
Here's a scientific study that might send a bout of collective laughter across humanity.
Followed by some obscure measuring.
And as much as I'd like to type just about anything else, CNN has deemed me the one to share this with you. So, here goes.
A new study suggests that dads with smaller testicles are more likely to be nurturing to their infants.
It was published Monday in the Proceedings of the National Academy of Sciences, which goes by the acronym PNAS (Yes, that's chuckle-worthy in this context, so go ahead and laugh).
Researchers at Emory University used an MRI to measure the gonads of 70 lucky biological fathers, age 21 to 43, in the Atlanta area. (Yes, they got paid for this.)
The scientists also studied each dad's brain pattern as he viewed photos of his child, a stranger's child or an adult stranger.
They were looking for activity in a part of the brain believed to be "involved in the motivation to approach and nurture offspring," said Emory anthropologist James Rilling, one of the study authors.
Meanwhile, the men's partners answered questions about how involved they were in taking care of their infant children. Do they take them to doctor visits or put them to bed?
The researchers then crunched -- sorry, bad choice of verbs -- the data.
"Fathers' testicular volume and testosterone levels were inversely related to parental investment," the study says, "and testes volume was inversely correlated with nurturing-related brain activity when viewing pictures of their own child."