Thursday, September 03, 2009

Mens' biological clocks are ticking, too By Dr. Tom Keenan, For The Calgary Herald


Still, for most of us, baby making is a game best played by the young. A study of more than 12,000 couples treated at the Eylau Centre for Assisted Reproduction in Paris found a man's fertility drops off in his late 30s and plummets after 40. The researchers also found if the father was over the age of 44, almost a third of the pregnancies ended in miscarriage.

They attribute this at least in part to a kind of "sperm decay," marked by DNA fragmentation and other abnormalities. Unlike women, who are born with all their eggs, men do not make any sperm until they reach puberty. Then we make up for it by generating up to 100 million new ones per day. Because of all this sperm-copying, mutations can accumulate with age.

Writing on,fertility specialist Dr. Carl Herbert likens the process to photocopying a cake recipe over and over until the "3 cups of flour" looks like "2 cups" and the recipe doesn't work any more.

"These subtle copying defects cause a long list of diseases in the children of older fathers," he writes. "Lesch Nyhan syndrome, polycystic kidney disease and hemophilia A are among the most well known. For fathers over age 40, the risk of having a child with a disease-causing mutation is similar to the risk the mother has for a child with Down syndrome." Other factors, ranging from high or low body weight to diabetes, can also adversely affect sperm quality....



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