According to new scientific research, the size of a man’s testicles can indicate how involved he is as a parent — the bigger the pair, the greater the drop in emotional responsiveness and infant care. In other words, being told you're a good father is now a backhanded compliment and an affront to your manhood.
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US researchers from Emory University in Atlanta investigated the link between testes size and parenting investment among men in a bid to shed light on Life History Theory, which examines potential trade-offs between mating and parenting (testes volume is associated with sperm production and testosterone levels).
To test their theory, the research team measured the testes volume of 70 biological fathers with children aged between one and two. The subjects then had their brain activity monitered via MRI scans in a region implicated in parental motivation as they viewed photographs of their child.
The men’s partners also filled out a questionnaire that queried the fathers’ involvement as a parent in common tasks such as taking children to health care visits or attending to children at night.
The study found that men with smaller testes were more emotionally responsive to their child’s face and more involved in infant care:
In response to viewing pictures of one’s own child, activity in the ventral tegmental area — a key component of the mesolimbic dopamine reward and motivation system — predicted paternal care giving and was negatively related to testes volume.
Our results suggest that the biology of human males reflects a trade-off between mating effort and parenting effort, as indexed by testicular size and nurturing-related brain function, respectively.
The report concludes that a fathers’ testicular volume and testosterone levels were inversely related to parental investment and testes volume was inversely correlated with nurturing-related brain activity when viewing pictures of their own child.
The authors acknowledge the possible influence of outside factors, such as fathers who experienced stressful and unpredictable childhoods growing up. Nevertheless, you may want to reconsider that "World's Greatest Dad" T-shirt next Father's Day.
We want to hear from big-balled dads and their pea-sized counterparts (hey, the internet is anonymous!) Do you consider yourself to be a nurturing, dependable father or could you be putting in more effort as a parent? And how does this relate to the size of your junk? Feel free to "bare all" in the comments section below.