A study from researchers at the University of Rochester shows that when it comes to a guy's fertility, size really does matter. But as Reuters Health reports, the dimension in question is not penis or testicle size, but a measurement known as anogenital distance (AGD), or the distance from the anus to the underside of the scrotum. According to the study of a group of 126 men, published March 4, 2011, in the journal Environmental Health Perspectives, men with an AGD shorter than 2 inches have seven times the chance of having low sperm counts ("sub-fertility") compared to those with a longer AGD.
According to study author Shanna Swan of the University of Rochester Medical Center in New York, the new findings may point to a relatively simple fertility screening test for men. "It's non-invasive and anybody can do it, and it's not sensitive to the kinds of things that sperm count is sensitive to, like stress or whether you have a cold or whether it's hot out," says Swan in an interview with Reuters.
Past research has shown that men with sub-fertility have about half the chance of conceiving as do men with normal sperm counts. While the AGD finding may mean nothing for the majority of couples, it could matter, especially if you and your partner are trying to figure out why you are having trouble getting pregnant.
"If somebody's got a short AGD, particularly if they have problems conceiving, I would say get to the infertility doctor, because the chances are good that something is wrong," advises Swan.