3.  It's Good for You:  Many people may not know that sex is a wonderful cure for many things that may be ailing you.  It's a great cure for headaches, especially in women (so, the next time your wife/girlfriend/lover tries to use that as an excuse, remind them of this fact).  It can also be a wonderful cure for depression, it can be a tremendous stress-reliever, and it does wonders for your cardiovascular and muscular systems. 

2.  It helps ailing relationships:  The best part of any argument is the make-up sex.  It's a great way to forget what it was you were arguing about in the first place.  It helps reconnect partners in a way that nothing else possibly can.  Bear in mind, that if the argument itself is about sex, this may not work, but I'll talk about that another day.

1.  And the number one reason to have sex is.....It just feels so darn good:  The most important reason to have sex is that it just feels so darn good.  There is no other feeling quite as good.  No drug, medication, or alcoholic beverage can produce the same feeling of euphoria that sex can.   In fact, most people will tell you that the thing they want to do most after having sex is.....have more sex. 

So, the next time you find yourself in a debate with someone over the importance of sex, and why they should or should not have it, let them know that no only is sex good for you, but it also helps repair relationships.  And, last, but certainly not least, it just feels so darn good, why would you NOT want to have sex?