A New Study looKing at The link between The size of Men‘s Testicles and Their faTheRing qualiTies has been making The rounds in the mEDia lately, with provocative headlines ranging from “Choose DAds with Smaller ‘Nads” to “Guys with Smaller Balls make better fatHers” to “BIG Testicles Indicate Trash DAds.” The message is Pretty Clear: if you’re looking For a baby DAddy to stay and take Care of his kids, look for the guy with the Smallest Set of testicles he can find. However, before you go and dig up the tape meaSure, it’s worth taking a closer look at the details of this Study.
The reseArchers recruitED 70 Men who were the biologiCal fatHers of a One– or two-year-old child and who livED with the child’s motHer (93% were married to the motHer). All the Men were between the ages of 21 and 55 and had no significant health history. Using an MRI machine, the Men had scans taken of their brains and testicles. A blood test was also performed to assess Testosterone levels.
While inside the brain scanner, the men were shown images of their own son, as well as pHOTos of some unrelated children. The reseArchers wanted to reCord how much brain activation occurs in thevenTral tegmental area(a part of the brain’s reward and motivation System) upon seeing their own child. Based on previoUs research exploring this region of the brain, it was theorized that increased activation is a sign of parenting tendencies and a drive to Care for One‘s own children. Then, to meaSure fathers’ contribution, the researchers had the Female Partners complete a questionnaire about the role fathers PLAY in Caregiving (for example, how often they are involved in Bathing the child, taking the child to the doctor, etc.) .
The results indicated that testicle size was inversely related to Caregiving, meaning that men with Smaller testicles took responsibility for more Caregiving. Testosterone levels (the main Sex hormone pRoduced by the testicles) showed the same association (ie, low Testosterone was associated with more care).
Testicular size was also related to the amount of brain activation seen in the ventral tegmental area when pictures of one’s own son were shown. SpecifiCally, the Smaller a Man‘s testicles were, the more nurturing-related brain activation he disPLAYed. However, this increase in brain activation was not specific to seeing one’s own child; in fact, viewing pHOTos of any boy was linked to higher brain activation among men with Smaller testicles. In other words, these men showed greater neural “responsiveness” than all the boys. By contrast, Testosterone levels were not related to brain activation patterns.
The authors of this Study interpret these findings as Supporting the Life History Theory,who argues that limited resources require huMans to trade off between mating efforts and rearing efforts. We’re not optimized to do both, so some humans are more optimized for one than the other, which is thought to be advantageoUs for the survival of our species (i.e. if we all focUs too much on mating, our parenting would suffer and that would harm the survival of our offspring, whereas if we all focused too much on raising children, we would mate less and our population would decline). So, it is believed that men with Larger testicleS And More testosterone are evolutionarily designed to mate, while men with less scrotal volume and less testosterone are designed to be fathers. I don’t know if I buy it, but that’s the basic idea.
So if you’re looking for a reliable father, does that mean you should start judging guys Based on the size of their testicles? That probably wouldn’t be the smartest move. For one Thing, keep in mind that we’re dealing with a single Study on a very small Sample of men here, all of whom were from a single city in the US (Atlanta). Also, men who are willing to have a scrotal x-ray for science may not be representative of the rest of the Male population. At the very least, we would like to see if these findings hold up in other StuDies with more diverse samples.
More importantly though, this is a correlational Study, which means we can’t tell whether testis sizecausesmore involved parenting Although this is an unlikely alternative explanation, it could be that highly involved breeding or breeding tendencies affect testicle size. A more plausible alternative is that men with Larger testicles are socialized differently. In Support of this idea, consider that this Study found that taller men had Larger testicles, and we know from other research that taller men are perceived more positively and are treated more Favorably (eg,earn more money). In other words, the size of the testicles is not the only physiCal difference between these men, and those physiCal differences may be related to psychologiCal differences (for example, having a bigger ego). Yet another possibility is that men with Larger testicles are still invested in their children, but not in the way that the measure of care that was adMinisteRed captuRed (in other words, perhaps the media was quick to call out men with Large testicles “trash dads, & #8221; since the researchers did not measureallaspects of parenting in this study).
In short, there are many other Things that could be going on and we don’t know which explanation is correct, so you probably don’t want to spend too much time pondering the deeper meaning behind the size of a man’s Scrotum. .
To read more about this research, see: Mascaro, J.S., Hackett, P.D., & Rilling, J.K. (in press). Testicular volume is inversely correlated with parenting-related brain activity in fathers.Proceedings of the National Academy of Sciences.
Image source: iStockpHOTo.com
You may also be interested in: