A new study out of Emory University found that testicle size plays a role in how active a father is in his child’s life. Men whose testicles were at the smaller end of the spectrum took a more active role in their child’s upbringing, including participating more often in mundane chores like changing the child’s diaper, getting the child ready for bed and giving the child a bath. The study has been published in the journal Proceedings of the National Academy of Science.
Researchers got the idea for the study after drawing parallels between mating behavior and testicle size in the animal kingdom. The theory evolved that animals with larger testicles spend more time seeking out a greater number of potential mates with whom to produce offspring, while their smaller-testicle counterparts spend less time engaging in mating behaviors.
An example in the animal kingdom which can be clearly seen is the difference between gorillas and chimpanzees. Gorillas have smaller testicles and are observed to be better fathers than chimpanzees, who have larger testicles.
Researchers also found that men whose testicles were smaller had more activity in their brains’ reward center when gazing at pictures of their offspring than did men with larger testicles. Those same men also were more apt to participate in the daily goings-on in their child’s life.
Scientists who conducted the study said there were some elements of it which were uncontrolled. Expectations placed on the men from society and culture were not taken into account, and all of the men, 70 in total, were from the same area.
Lead researcher Dr. James Rilling said, “It tells us some men are more naturally inclined to care-giving than others, but I don’t think that excuses other men. It just might require more effort for some than others.”
While the exact reason for the link is unclear, scientists think it may be connected to the hormone testosterone. Testosterone may account for governing some types of behavior in men, and those with smaller testicles may sometimes tend to make less of the hormone than their counterparts.
In addition to the lingering questions about the exact reason for the link between small testicles and parenting behavior, scientists also have a “which came first; the chicken or the egg?” type of dilemma on their hands. Dr. Rilling said, “Environmental influences can change biology. We know, for instance, that testosterone levels go down when men become involved fathers. We’re assuming that testes size drives how involved the fathers are, but it could also be that when men become more involved as caregivers, their testes shrink.”
This indicates that the study cannot confirm causality, but rather that it indicates a correlation. The study authors also point out that much more research needs to be done to determine exactly why the correlation between small testicles and better parenting exists.
So no worries, Dads. It’s not time to get out the old measuring tape and begin a thorough examination of the family jewels just yet. This is an emerging field of study that could pave the way for future research and eventual benefits to fathers everywhere, but much more work needs to be done to determine why the link between small testicles and being a better father appears to have been confirmed.
By: Rebecca Savastio