all joking aside, this is a gigantic market. people with STDs are hiding and do not want anyone to know (even doctors) out of embarrassment. you're going to provide them with a all-encompassing-wonder-solution they can order online that will fix the problem privately.
goldmine.
there is even a huge market for ebooks on how to get rid of STDs (seriously). it's one of the first niches i got into back in the day.
Reminder: anything embarrassing has a gigantic online market.
edited: I forgot to tell you the worst part tho... keep in mind that you'll be making landers that discuss stds and using images of "body parts" with sores and shit on them. it's disgusting to work on but if you have the stomach for it... go for it.
just dont be surprised when your girlfriend walks in unexpectedly and says "OH MY GOD what are those pictures?"