I have an opinion and it is not daddy's wigglers but from Mom's.
Men produce sperm but woman are born with a lifetime of eggs.
Also women may have medical conditions that can pass through the placenta.
I would put my money on some chromosome/genetic flaw in the womans older eggs.
Why are you assuming that if the father is over 60, the mother can't be under 40?
Yes, you may be correct. That's the intersting thing about this that I didn't see in the study. What were the ages of the women. Chances are that if the man is older that his spouse is also. How did they control for the age of the woman?
That's right, blame the woman.
Just like for centuries it was women's fault when the men didn't have any boys.
Too bad they found out it is the man's fault.