For fertility, size does matter
The dimension in question is not penis or testicle size, but a measurement known as anogenital distance.
Men whose AGD is shorter than the median length - around 52 mm - have seven times the chance of being sub-fertile
as those with a longer AGD, according to a study published in the journal Environmental Health Perspectives.
That distance, measured from the anus to the underside of the scrotum, is linked to male fertility, including semen volume and sperm count, the study found. The shorter the AGD, the more likely a man was to have a low sperm count.
This offers the prospect of a relatively simple screening test for men, said study co-author Shanna Swan.
"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," Swan said.
"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."Have you or your partner been tested for a short AGD? Share with us below.