Sex is a special act that is a joining of a man and a women who are married. Sex is a way of showing love and devotion to your spouse. Sex should be used in love, not just a "thing to do".
Teen sex is out of the question! By having sex with a boyfriend or a girlfriend, you do not show them that you are devoted to them. After you have sex your relationship takes a turn that teens are not ready for. If the teen is ready for making love then they should be ready for marriage. But no teen is ready for marriage until they graduate from high school. No teen is ready to have a child. They are still children themselves. They need to have their own fun. They need to get into their own trouble. How can someone be a good daddy or mommy if they have not experienced these things. Teens need a chance to be with their friends, not tied to a baby.
Adult sex between unmarried men and women is also out of the question. How can we show kids that it is bad if they see adults doing it. Adults of all people should realize that sex is something special. It should be shared between a married man and woman.

If all men and women wait to have sex until they are married, then we would wipe out a lot of STD's.