New lab studies suggest the little blue pill may impede fertility, and so the researchers say “recreational users” should be informed the drug may hurt their sperm function.

“Given that the majority of sperm acrosome react on exposure to (Viagra), the drug may cause significant impairment to their fertilizing potential,” they write in the Fertility and Sterility journal.

Of course, not every guy may be upset to hear this. For some, it may taken as a green light to have more unprotected sex. And this is where Pfizer turns a liability into a brand new marketing opportunity, right?

Younger fellas, who don’t want to have kids, may now think of Viagra as not just a party drug, but a form of birth control. And for those older gents with erectile dysfunction, well, they may now be further emboldened to pursue those elusive May-December relationships, and not have to worry about appearing to be an offspring’s grandfather, instead of….daddy.

In their experiments, David R. J. Glenn and his colleagues observed that exposure of cultured sperm to Viagra, compared to no exposure, led to a “sustained enhancement of motility,” both in numbers of progressively motile sperm and their velocity.

However, exposure to Viagra - at concentrations equivalent to the average maximum total blood concentration present 30 minutes after a single oral dose of 100 milligrams - also caused a premature “acrosome reaction.” Acrosomes are structures that cover the head of the sperm and contain a variety of enzymes that help the sperm penetrate the outer membrane of the egg.

That Viagra may induce early activation of the acrosome reaction has “important clinical implications because sperm that acrosome-react before contact with the oocyte are incapable of fertilization,” the researchers note.

This is a concern, Glenn and colleagues say, given that Viagra and other like-drugs are widely available on the Internet and are increasingly being used “recreationally” by young healthy men of reproductive age as sexual enhancers - not just by older men who have erectile dysfunction.

Source: Reuters