London: June 3, 2008 - When it comes to fertility and the prospect of having babies, it has always been assumed that men have no biological clock — unlike women, they can father a child late in their life. But a study has dispelled this myth.

Researchers in Europe have found that children are almost twice as likely to die before adulthood if they have a father over the age of 45 years, a key finding they claim is linked to the declining quality of sperm as men age.

According to them, children of older fathers are more likely to suffer from particular congenital defects apart from autism, schizophrenia and epilepsy.

"The risks of older fatherhood can be very profound, and it is not something that people are always aware of," Jin Liang Zhu of Danish Epidemiology Science Centre, which carried out the study, was quoted by the Sunday Telegraph as saying.

The researchers came to the conclusion after examining 100,000 kids born between 1980 and 1996, of whom 830 have so far died before they reached 18 — the majority when they were less than a year old.

The deaths of many of the children of the older fathers were related to congenital defects such as problems of the heart and spine, which raises risk of infant mortality, the study revealed. The study was published in the European Journal of Epidemiology .