When it comes to performance-enhancing drug tests, sometimes things can be tricky. Take, for instance, the memo Major League Baseball reportedly sent out on Monday warning all players about the potential risk of ingesting over-the-counter sexual-enhancement pills. No, that isn't a joke; yes, MLB really sent out a memo on that subject matter. 

Here's a snippet of it, courtesy of ESPN.com's Jeff Passan:

"Sexual or male enhancement products present a very real risk for drug-tested players," the memo said, "and the high likelihood for contamination or unidentified ingredients in these products underscores the importance of consuming only those products that are NSF Certified for Sport."

The memo was precipitated by a couple of players arguing their failed PED tests were the result of taking these over-the-counter supplements. Of course, as MLB notes in the memo, ignorance of what is contained within the product -- and the product's intended effects -- do not excuse a player from the punishments that are triggered by a failed test.

That may seem cold-hearted on MLB's part, but to be fair they do note in the memo that any player suffering from erectile dysfunction or other sexual-performance-related issues should "speak to a licensed physician about the various prescription medications." 

This isn't the first time PED-testing has included drugs intended for sexual or reproductive purposes. MMA fighter Jon Jones was suspended for taking male-enhancement pills a few years back. It's worth noting that Jones's explanation was that he "just figured [checking the testing rules] wasn't needed because it had nothing to do with sport performance."  

Meanwhile, Manny Ramirez tested positive in 2009 for human chorionic gonadotropin -- a drug typically used by women to improve conception. You can read more about Ramirez's case in this Scientific American explainer