If you want to get into the weeds of any herb you'll need to go further than the Google machine, which is gamed and only prints what is gamed unless you go into it 50 pages. There are many books on the use of herbs. Herbalists are good sources of information. There is a trade association you can contact for sources of info. All that being said, I don't know of any such side effect. Keep in mind you seem highly focused on your genitalia, and when you do that, you can think yourself into things that might not be there otherwise, but my not knowing that's a side effect doesn't mean it can't ever be. The biggest warning about this herb is sun sensitivity. But again, there are many really good herbals out there that discuss in some detail. There are books just on St. John's Wort, as it's such a commonly used herb.