Small balls = Great Parenting Dads
This has nothing to do with football, tennis or ping pong, although ball games are an important part of a father's parenting input.
This has to do with testosterone and testicles.
A research team at the University of Atlanta has discovered a link between smaller testicles and better fathering skills.
The scientists measured the testicular volume of 55 dads and then asked a series of questions to them and their partner about their involvement with their children. After this the men’s brain activity was measured while they looked at photos of their off-spring.
Although bigger testicles usually contain best quality sperm, the men with small testicles gained the best scores for empathy and child care skills.
The team admitted that it was a bit of a chicken and egg situation. They were uncertain whether smaller testes led to better parenting properties, or whether interaction with children led to dampening down of testosterone and hence testicle shrinkage.