Cross-posted at Girl W/ Pen
So… I’m going to go ahead and say that this is the wrong question to be asking. This question proceeds from a belief that testicles CAN tell us something about dads. A new study is making the rounds in the news that addresses the relationship between testicle size and parenting behavior among men (well… 70 men… not randomly sampled…). The paper is entitled “Testicular Volume is Inversely Correlated with Nurturing-Related Brain Activity in Human Fathers” in the Proceedings of the National Academy of Sciences of the United States of America. I can think of more than a few titles that might have been catchier (and clearly, journalists reporting on the research had a similar idea).
In fairness, I don’t have access to the complete study (though I’ve requested it). But the problem is also in how this study gains attention in the media. It’s a great example of how a correlation combined with cultural stereotypes and assumptions can run wild. When correlations combine with popular stereotypes concerning a particular topic (like, say, the relationship between testosterone and any number of socially undesirable behaviors), questions about the science sometimes get lost because it looks like something was “scientifically proven” that we already wanted to believe anyway.
So, here’s the relationship the researchers found: men with smaller testicles tested more positively for nurturance-related responses in their brains when shown pictures of their children. The study reports that men with smaller testicles had roughly three times the level of brain activity in the area of the brain associated with nurturing. These men (with smaller testicles) were also men with lower levels of testosterone—something that has previously been shown to be associated with nurturing behavior among men.*