Before I say this next line, I'd just like to inform you all that no, I'm not Hitler, and no, I don't plan to carry out this statement in any way or form. K?
Think of what would be without the human race.
It would be much better for the rest of the earth. Humans aren't a keystone species at all; it's not to say that we aren't important but that we are not living within the world as much as we are living above it. Reproduction is natural, but carrying capacity is as well, and carrying capacity happened hundreds of years ago. Technology is natural to a point, but we have influenced our own carrying capacity through it. Medicine in its herbal forms is natural, but in our every day methods? Not really.
One might argue that if it happens, it is natural, but in the same way that climate change is not natural (ten years ago you could have argued that point too; not so much now), human's lifestyle is run by humans, not the world. It sounds simple, but it's a very, very unusual phenomena. In other words, no other species can pull it off.
So to wrap this back around to sex with as many girls as you can think of, that's weird too...