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Posted on May 31, 2003, 7 a.m.
By Bill Freeman
Is seems that it's not just women who have a "biological clock" controlling their fertility, as new research confirms that men have one too, although it appears to tick a little more slowly. "Progressive motility" describes a sperm's ability to swim fast and aim hard at its goal - the egg. Results of a study by Brenda Eskenazi and colleagues at the University of California in Berkeley found that that this "progressive motility" declines at a rate of 3.
Is seems that it's not just women who have a "biological clock" controlling their fertility, as new research confirms that men have one too, although it appears to tick a little more slowly. "Progressive motility" describes a sperm's ability to swim fast and aim hard at its goal - the egg. Results of a study by Brenda Eskenazi and colleagues at the University of California in Berkeley found that that this "progressive motility" declines at a rate of 3.1% a year. Thus as men get older their sperm slow down and become less goal-orientated - seemingly preferring to swim in circles instead. A woman's fertility is known to drop significantly around her mid-30s. In the past, it was thought that men did not experience such a marked drop in fertility, however the results of this study suggest that a 30-year-old man has roughly a 50% chance of having abnormal progressive motility. By 50, the chances of abnormal progressive motility increase to 67%, and by 80 to 84%.
SOURCE/REFERENCE: Human Reproduction 2003;18:447-454
