While there is no evidence that women having babies when they are older has an adverse influence on the child’s upbringing (older women often have better life skills and may be more able to afford better child care support) it’s not the same for men.
Older men pass on three times as many mutations in their genes than younger men.
The research published in Nature showed that older men were more likely to have children who later suffered from autism or schizophrenia.
The researchers from Reykjavik studied family genomes and found that while a 20-year old man passed on 25 new mutations to his child, a 45-year old man passed on 65, and that every additional year that a man delays having children adds about two additional mutations.
Men in their 80s coud pass on as many as 150 new mutations whereas women, regardless of their age, passed on fewer than twenty.
And research in Malaysia, published in 2011, showed that people with older parents, or where their father was as least 11 years oder than their mother, were at an increased risk of mental disorders including anxiety and depression, OCD and phobias.
Children whose fathers were 19 or younger when they were born had only 1 9% prevalence of mental health disorders. Ignoring paternal age the 11 year age gap mentioned above increased the risk of mental ill health to 24%. The greatest risk was to children born to fathers aged 50 or over with wives at least 11 years younger tan their husbands.
So is this about deteriorating sperm related to the ageing process alone? Probably not. Epigenetic factors (the impact of the environment, including drinking and smoking, on your genes which you then pass on) as well as psychological and social influences are all likely to play a part
So men are fertile longer than women but the quality of their sperm cells deteriorates – a good argument for young men having their sperm frozen.