Biological clock doesn’t just tick for women... men cut chances of being a father after age 40

IT is not just women who need to worry about the ticking of their biological clock.

Men who wait until their 40s to try to become fathers could cut their chances by more than a third.

A US study has found that men aged 40 to 42 with a female partner who is under 30 have an average birth rate of 46%.

This is more than a third below the 73% rate for men aged 30 to 35.

Experts believe sperm DNA becomes damaged with age, which explains the higher risk of older men having children with autism and schizophrenia. Men aged 40 to 42 are a fifth less likely to have a baby than before their 30th birthday, the results suggest. The findings, for couples having IVF, suggest women are better off trying for children with a man their own age or younger.

Commenting on the research by the Beth Israel Deaconess Medical Centre in Boston, expert Professor Nick Macklon, from Southampton University, said: ‘I suppose from the social side the value of this is not only in counselling couples about when to move for ART [assisted reproductive technology], but it may help women encourage their male partners to get a move on.’

Scientists analysed data on 7,753 couples seen at a Boston fertility clinic between 2000 and 2014. Their results suggest women who have put off trying for a baby are much better off finding a toyboy if they want to fall pregnant. Those aged 35 to 40 were almost 30% more likely to have a child with a partner aged below 30 than one aged 30 to 35.

Lead researcher Dr Laura Dodge said older men trying to conceive naturally were less likely to get women pregnant, took longer to do so and increased risk of miscarriage. This may be due to DNA damage and changes to genes.

The US study, presented at the European Society of Human Reproduction and Embryology conference in Geneva, Switzerland, found women saw their chances of a live birth fall 46% from when they are under 30 to aged 40 to 42. But men cut odds of having a baby by 20% over the same time. Dr Dodge said there was little men could do to counteract the effect of age on their sperm, adding: ‘The best preconception advice we can offer is to maintain a healthy lifestyle.’