Looks like women aren't the only ones who need to worry about their biological clock when it comes to having a baby. A new study indicates that the quality of men's sperm declines with age.
Women's fertility decreases until menopause, when ovulation ends. In contrast, men produce sperm throughout their lives. However, the sperm of an elderly man don't equal those of a young one, Brenda Eskenazi of University of California, Berkeley and her colleagues report in the February Human Reproduction.
The researchers studied sperm samples from 97 volunteers ranging in age from 22 to 80. None of the men had any known fertility problem. Semen volume decreased with age, as did sperm motility, the researchers found. The tendency of sperm to move in a single direction, as opposed to randomly, also dropped as men aged.