The MALE biological clock: After 41 your chances of becoming a father 'declines rapidly'

By Fiona Macrae
It is not just women that have to worry about their biological clock.
Male fertility declines with age – with even a year making a difference, researchers have warned.
They say that after the age of 41, a man’s odds of fathering a child decline rapidly.

 

And after 45, those who haven’t started a family and want one should start doing something about it.
But with the likes of Des O’Connor having his fifth child at 72, and Rod Stewart becoming father for the eighth time at the age of 66, other experts said the finding should be taken with a pinch of salt.
The warning comes from a study of IVF patients in which the man’s sperm fertilised an egg from a donor.

In the context of the study, the use of donor eggs allowed the researchers to separate out the effect of the man’s age from that of the woman’s.

The donor eggs all came from young, healthy women and so any differences in pregnancy rate must be due to the sperm.
And the difference was clear, with fertility declining by up to seven per cent with each extra year on a man’s age between 41 and 45.  After that, it declined even more rapidly.
The average age of the men whose partners got treatment through IVF was 41.  

 But the average age of those in which the IVF was unsuccessful was 45, the American Society for Reproductive Medicine’s annual conference heard.

The chances of pregnancy fell from 60 per cent at the age of 41 to just 35 per cent for the 45-year-olds.
Researcher Paula Fettback, of the Huntington Medicina Reproductiva clinic in Brazil, said: ‘Age counts 
‘Men have a biological clock too.  It is not the same as for women but they can’ t wait forever to have children.
‘They have to think about having children, especially after 45.’ 
A second study presented at the conference backed up the warning.
There, fertility plummeted in male mice from a year old – equivalent to middle-age in people.
Fewer eggs were fertilised and fewer embryos grew long enough to be used in IVF.
Pregnancies took longer to occur and when they did, the miscarriage rate rocketed from zero using sperm from young animals, to over 60 per cent.
The researchers, from the Colorado Center for Reproductive Medicine, said they believed there would be ‘some parallel’ with men.
‘We found an abrupt reproductive deterioration in mid-life, equivalent to humans in their 40s.’ 
Other studies have found that children of older fathers also run an increased risk of heart defects, autism, schizophrenia and epilepsy, and are almost twice as likely to die before adulthood.
While men constantly make fresh sperm, the ‘machinery’ that makes it can slow down and become defective over time.  In addition, genetic errors may creep into sperm as men get older.

But other experts said advised would-be fathers not to worry