Short after my previous entry discussing how a man's age affects his fertility comes another research study indicating that obese men may have difficulty in fathering a child, too.

The analysis showed that the men in Group B, who had an optimal BMI (20-25, as classified by WHO), had higher levels of normal sperm than those in the other groups. They also had higher semen volume. There was no significant difference between the four BMI groups in sperm concentration or motility.

The researchers did not look at DNA damage in the sperm, preferring to look at the parameters of the routine semen analysis, which all men attending the fertility centre will have at least once. "Other studies have suggested an association between male obesity and increased DNA damage in the sperm, which can be associated with reduced fertility as well," said Dr. Shayeb.

"Our findings were quite independent of any other factors," he said, "and seem to suggest that men who are trying for a baby with their partners, should first try to achieve an Ideal Body Weight. This is in addition to the benefit of a healthy BMI for their general well being.

Although it is not yet clear how obesity affects semen quality, these initial findings indicate that being overweight do contribute to fertility problems, not only among women, but also among fathers-to-be.