Size May Matter When It Comes to Male Fertility
What seems to factor in to the ability to father children, according to the study in Environmental Health Perspectives, is something called anogenital distance, or AGD — not penis or testicle size.
Men with an AGD that’s shorter than the median length of 2 inches are seven times as likely to be fertility-challenged, or “sub-fertile,” than those with a longer measurement, say the researchers from Rochester Medical Center.
The AGD is the distance between the underside of the scrotum and the anus. The shorter that measurement, the better the odds that a man will have a low sperm count, says study co-author Shanna Swan.
“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,” Swan told Reuters.
But a well-known male fertility expert scoffed at the findings.
“This is just patently absurd,” Dr. Sherman Silber, the head of the Infertility Center of St. Louis, told AOL Health.
He said the AGD is never used by fertility specialists as a significant measurement or sign of trouble conceiving.
“The anogenital distance from the bottom of the scrotum to the anus is very subjective and variable,” Silber said. “No one normally measures this, and so they had to have a goal in mind to try to prop up their position.”
Swan’s team took AGD measurements for 126 men born in 1988 or later and say they noticed a link between its length and sperm count as well as semen volume. They didn’t look at why some men had shorter AGDs than others.
Prior research from 2005 and 2008 found a potential correlation between the AGDs of infant and toddler boys and their mothers’ exposure to toxic chemicals known as phthalates, which are found in some pesticides, plastics, personal care products like soap and shampoo, and paints, Reuters said.
Swan, a co-author of the previous studies, and colleagues tested the expectant moms for traces of phthalates in their urine, finding that those with higher levels of the chemicals had baby boys with 10 times greater odds of having shorter-than-average AGDs.
The current paper focuses more on “why we should care about AGD,” Swan told Reuters. “It does suggest that whatever is altering AGD is also altering sperm count.”
The findings could pave the way for a new fertility test for men.
“It’s non-invasive and anybody can do it,” Swan said. “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.”