0301 GMT November 20, 2019
Older men were found to have a lower chance of conceiving than younger men with a wife of the same age, BBC reported.
Harvard researchers presented their study of nearly 19,000 IVF cycles at the European Society of Human Reproduction and Embryology.
The findings contradict the idea that male fertility goes on forever.
In fact, whether conception is natural or assisted, sperm mutations and a decline in sperm count in older men are thought to reduce the chances of pregnancy.
Previous research has also shown that older sperm is more prone to genetic errors, and this has been linked to the development of autism and schizophrenia in children.
But the age of the woman still has a larger impact on fertility than the man's age.
In this study, scientists found that men aged 40-42 were linked with a 46 percent lower chance of having a baby by (IVF) than men aged 30-35, when the wife was under 30.
Thirty-five year old women had significantly more success with a husband under 30 after one cycle of treatment, than with a man in his mid-30s.
Nick Macklon, professor of obstetrics and gynecology at University of Southampton, said, "This may encourage men to get a move on.
"It also offers new insights into the dynamics between the man and woman — it's not just down to the age of the woman."
Dr. Raj Mathur, consultant gynecologist and clinical lead for reproductive medicine at Manchester Fertility, said, “The issue of men's age and its impact in IVF needed to be researched further in a larger database of couples.
But he said, "We should start taking male age into account."
Dr. Gillian Lockwood, medical director, Midlands Fertility Services, said, “There were distinct differences between women's and men's fertility.
"Women are born with all their eggs and don't make any new ones, but men make new sperm every morning.
"That's where errors can creep in as a result of cell division.”
She said that there was more chance of the woman becoming pregnant if both couple were young and added, "But if they both wait until they are older, then that could be more problematic."