Sex
Sometimes, when two people love each other very much, or are very broke, they will engage in a magical, mystical human mating ritual. We call this "sex." Sex is a beautiful thing, not to be dismissed lightly by the non-sexual 95% of the population.
Sex can also be a dirty, sick, depraved thing, full of pain and clothespins and candle wax and rope and extruded plastics and video cameras, and this is the kind of sex you'll be throwing down wads of hundreds for unless you're very, very lucky in selecting a mate.
If performed improperly, sex can lead to pregnancy, divorce, intense self-doubt, and shingles. Medically, there is no purpose for sex. There's already plenty of people out there. I recommend avoiding sex unless you absolutely cannot avoid it. Just tell 'em Dr. Joe said no!