You might want to start by looking up the way sperm is being produced. It will help you clear the confusion with the link between the mother's age and birth defects.
Although citation is needed, if I remember correctly, because of lacking healthy young Japanese men after WWII, ageing fathers' sperm contributed to at least as much to newborn malformations as the nuclear fallout.
But the thread also tells you about the euphemism under the guise of 'ego' in the article, and how society today is structured (ie. power of the old vs. youth in our times). At his age, he should clearly let go, by all standards, even if it so difficult. To quote a famous speech from another control freak who at least knew all about this, luckily Nature has provisions because it "clears out the old, to make room for the new. Right now the new is you. But you won't always be."
It's interesting that you mention the Japanese, because when I looked into it awhile ago, I could find no evidence of any increase in birth defects following the bombing. I could swear that we had pictures of deformed children in a textbook as a kid, so I started Googling it, but the only things I turned up said "no statistically significant increase".
Thought this was important enough to reply again. Wikipedia:
> In 1933, Lionel Penrose analyzed data for 727 children in 150 families and found no paternal age effect for the risk of Down syndrome after controlling for the maternal age effect. Largely based on a 2003 paper by Fisch et al. that found a paternal age effect only "in association with a maternal age of 35 years and older", a 2009 review of the literature subsequent to Penrose's paper concludes that "a paternal-age effect exists, but is very small in comparison to maternal-age effect in Down syndrome prevalence".
In principle, I suppose this is compatible with what your article stated:
> "Older fathers may contribute just as much as older mothers to the dramatic increase in Down syndrome risk faced by babies born to older couples. A new study found that older fathers were responsible for up to 50% of the rise in Down syndrome risk when the mother was also over 40.
I'm not sure how many conflicting studies are out there and factored into the 2009 review.
Down syndrome is only one possible birth defect. If you were to look up information on American sperm donation procedures, you'd find that there are estimates that use of donors leads to 1/5 the defects in part due to younger age and rigorous selection criteria - which strikes me as a powerful testimony to how much sperm quality can matter: http://en.wikipedia.org/wiki/Sperm_donation#Sperm_donation_a...
