How can a mother firmly tell her teenage son that her decision to let him date does not mean he is allowed to have pre-marital sexual intercourse at home or anywhere else?

You didn't mention if his father was living at home as well. He should be the one having "the talk" with your son. However, kids today as young as 10 know more about sex than most of us did at 15 - 16. You have every right to have rules in your house, but, you have absolutely no control over your son once he's away from home. All you can hope for is the fact you teach him that although you don't approve of him having sexual relations he should learn that sexually transmitted diseases are at an all-time high as well as young girls getting pregnant and he should ALWAYS wear a condom. Let him know if he should get a girl pregnant he has 50% of the responsibility of raising a baby. Telling your teenager they CAN NOT have sex is like putting a red flag in front of a bull! Discuss it with him on an adult level and let him simply know what you know. Then pray! ===ANOTHER ANSWER=== IF YOU ARE allowing your son to date, you have the right (and responsibility) to have strict rules and guidelines in place. By now he should have had "the talk" and be well informed about diseases, pregnancy etc... Many parents fear that if they inform their children about condoms etc... they are saying it's o.k. to have sex. But in reality, teenagers already think about it and if they are so anxious to find out what sex is about, they will do it on their own anyway. At least if they are informed, they can make better, well informed decisions, even if it makes us cringe and a little crazy. A responsible parent will let them know how we feel, we don't want them engaging in sex, what the rules are etc... But at least we know that they know the facts and the rules and our feelings on the subject, and if we've done a good job raising them, we will be better off in the long run. Then.....hope for the best.....and as Marcy says, "PRAY"!