It takes big balls not to help with diaper changing and feeding and bathing the baby.

Or something like that —  according to a new and purportedly scientific study reported at BBC.com.

Be careful, ladies, about bragging to your friends about how much your man is helping with the baby. You may be unwittingly revealing that his testicles are small.

And, note, the scientists can't say which came first, the testicle size or the degree of helping with the baby. So getting the man to help might cause shrinkage of the testicles.

So men, asked to help, might beg off using a testicle-size-maintenance argument.