Men With Big Testicles Less Likely To Be Caring Fathers, Study Shows.

Men with larger testicles tend to be less involved fathers than those with smaller testes, a new study suggests.

The findings, detailed today (Sept. 9) in the journal Proceedings of the National Academy of Sciences, are correlational, so they can't say exactly why the trend exists but only that there is a link.

But men who produce more sperm have bigger testes, and sperm production is extremely energy intensive for the body, so it may be that fathers "face a trade-off between investing energy in parenting and investing energy in mating effort," said study co-author James Rilling, an anthropologist at Emory University in Atlanta. [Sexy Swimmers: 7 Surprising Facts About Sperm]

Involved dads

Scores of studies have shown that children with involved and caring fathers tend to do better emotionally, socially and educationally. read more...