Size is no guarantee of anythingIn the evolution of good parenting
Equipment size science is Gonads
To work out the suitability of dads
A thesis composed on the Testes
Is not one of our science’s besties
I rather fancy it is all wordy balls
Where funding has made all the calls
I shall walk over dale and hillocks
Think to myself, this is just bollocks
Guardian nad other press - Men's aptitude for childcare may be reflected in the size of their testes, according to a study by US scientists. Researchers found that men with smaller testes were more likely to take charge of children's bath-time, visits to the doctor, night-time comforting, and other parenting jobs than others who have larger testicles.
The same story was borne out by brain scans which showed that men with smaller gonads reacted more strongly to photographs of their own children than did men with larger ones. The findings are the strongest evidence yet that variations in male anatomy reflect competing evolutionary strategies that can be distilled down to mating as much as possible versus investing more in parenting. Both are effective ways to maximize an animal's chances of having offspring that continue their lineage.