YES. Attend:
"Son, If you have sex outside of marriage you will eventually get a sexual disease. It may even be a fatal disease. You may get the girl pregnant. If so, you will be responsible for that child until it is adopted or until it is 18. You are worth far more than throwing your future away just to fulfill your lust. You will also seriously harm your future married sex life. It's far better to save yourself until you are married."
"Daughter, if you have sex outside of marriage you will eventually get a sexual disease. It may even be a fatal disease. You may also get pregnant. Remember that no contraceptive method is 100% effective and that you will bear responsibility for that child until they are adopted or until they are 18. You are worth far more than selling yourself to someone you would not marry. It's far better to save yourself until you are married."
What's so hard about that? I've told them all they need to know about premarital sex. "Don't, you'll eventually get caught". If I've raised them correctly up until that point it will never be a problem.
[Truthful disclosure time, I have one child, a daughter, who is the worlds most beautiful 13 month old angel. But when she's older this is how I'll teach her aout sex. It's for married people only.]
GSA(P)