The study published in “ Nature “ confirms what was suspected long before the human genome could be sequenced – that whereas a woman’s eggs are formed early on ( while she is still in her mother’s womb ), sperm are made continuously throughout life. Each division of cells producing sperm brings a risk of mutation.
• The ” sensationalist “ reporting by the BBC does need to be put in context. This was a genetic analysis of 78 trios of father, mother, and child, who are still alive. The research team looked for mutations in the child that were not present in either parent. Fathers passed on nearly four times as many mutations as mothers. The numbers of new mutations being passed on increased with paternal age. ( Drugs such as “ Viagra “ have many side effects, but causing mutations is not one that is recognised ).
• Most mutations have little effect. Possibly 10% are damaging, and a smaller proportion are beneficial – that’s natural selection / evolution. Older fathers and mutations may be linked to conditions such as autism and schizophrenia because the brain requires many genes for development. Even if these uncommon disorders increase in frequency, most children born to older fathers are still going to be healthy.
• In Iceland, where the study was carried out, and countries such as the UK, if the findings are confirmed, any negative effects of extra mutations due to increasing age of fathers at conception are likely to be balanced by positive effects of modern life such as better nutrition, hygiene, and sanitation, and better medical care. In the Philippines, where health of mums and kids is already a cause for concern (http://filipinaroses.com/showthread....ippines-and-UK ), fathers of any age should have more important things to worry about than their contribution to mutations in their children.
• Already some women – for example having cancer-related gynaecological surgery – have eggs frozen before their operations. While there is some evidence now that offspring of older fathers have an increased risk of genetic disease, not many will feel the need to have their sperm frozen while they’re young, in case they find a willing partner in their old(er) age.