Anders78 Third stat is Fame.
When you just start out, "true" visitors and fans are pretty much all you can get, but eventually the horndogs are going to take over and make up the majority of visitors. If you already built up notoriety and get alot of sex offers, then you can focus on the female visitors since they never ask for sex, all of them are either actual visitors or fans. Also, you could try rejecting sexual advances to drop notoriety, that will shift the balance back towards non-sexual visits.
That is all that comes to mind...unless you decide to edit the game files, but at that point you could just make it so male visitors no longer appear at all or something like that.