But scientists at McGill University now think that it might be a biological imperative.
Their hypothesis is that ” in younger women the egg can correct any defects in the sperm. The sperm is mainly a delivery device for genetic material but the egg is more complex. (So) in younger women the eggs are such that they can fix any defects …. but once a women hits 40 that is no longer true”.
It explains the cougar phenomenon of older women wanting to mate with younger men rather than risk mating with older men whose sperm quality has deteriorated.
Fertility experts at Oxford University also said the theory made sense as eggs are really rich in enzymes that repair DNA.
So there will be a tipping point where the sperm is deteriorating and eggs are losing the capability to repair DNA defects. This is definitely one are of human activity where older is not necessarily better (in fact now I’ve written that I’m wondering if there are any such activities but moving on…) and it seems younger parents have healthier children.
Of course older parents are probably more economically comfortable and more emotionally mature so there’s always a trade-off.
At the same conference in Hawaii (American Society of Reproductive Medicine) where this research was presented another scientist reported that men over 45 were more likely to have children with psychiatric disorders such as autism or schizophrenia.