Overweight or obese men, like their female counterparts, have a lower chance of becoming a parent, according to a comparison of sperm quality presented at a European fertility meeting.
In what they described as the largest study of its kind, doctors looked at sperm samples from 1,940 men and matched them to the donor's weight.
The benchmark was the body mass index (BMI), a measure of body fat among adults. Under this, normal weight is defined as a BMI of 18.5-25; overweight as 25-30 and obesity as 30 or more.
The higher the count in excess weight, the more the sperm quality suffered, especially among those in the obese category, according to the findings, presented at the annual conference of the European Society of Human Reproduction and Embryology (ESHRE) in Stockholm.