Only thing wrong with this advise is that it goes against God's word...
Which is a big deal imo.
What exactly does God's word say on this matter? In the old testament, you if you found two people having sex, they would be married, regardless of their maturity ability to have a family. No where in the Bible that I am aware of does it say not to marry because of immaturity. There are verses in Song of Songs saying to not awaken love too soon, but this relationship has already passed that point.
I basically did not date growing up, more of a personal choice than something forced on me by my parents, and to a large extent I regret it. Yes, it helped avoid sexual impurity, but it has made for entering relationships now much more difficult. Of course, there is a middle ground between no dating and dating that includes two people, in private, away from any sources of accountability. Some people may call this middle ground courting, group dating, or a vast possibility of other names.
Of course, the issue here isn't about raising a child who avoids sexual immorality, but what is to be done about the teen in question.
As to the question of birth control/protection... would you provide your child with a helmet if he wanted to ride a motorcycle, even though there is no justifiable reason for a Christian to put their body at risk (motorcycles on the road are dangerous). Would you make sure a professional double checked him parachute before he sky dived, even though he is putting his temple of God at an unnecessary risk?
One might bring up avoiding any appearance of evil, but what exactly appears evil? Perhaps it appears that you are condoning the relationship by not disowning him. Should you disown him to ensure you are not appearing to condone the relationship?
In the same way is how I see providing protection.
Now, what you should do is get both him and her to sit down and talk about marriage. In the Old Testament they would have been married the first time they were caught together. In the New Testament, Paul says it is better to remain unmarried to serve Christ Jesus, but to avoid sexual immorality, it is better to marry than to burn with passion. Culture says they are too young, too immature to get married, but this is the same culture that says it is acceptable for them to have sex. I'm pretty sure we are already no listening to culture.
If they don't want to get married, why? In that why, in the reason they don't want to get married you may find the key to convincing him to stop the relationship from being sexual.
NJBeliever said:
Parents force their kids to do things all the time. What if your child decides they don't want to go to school for a month.
How exactly would you force this relationship to stop. Depending upon the law, if she is younger, you can bring it to the attention of the law, but all you do then is ensure his life is ruined. Our society gives little power to parents to end their children sexual behavior. If it was a gang, the law would help you get him out of it. If he was skipping school, the law would help. But here, either the law will punish him greatly (if the relationship qualifies as statutory rape), or the law says "What they are doing is ok with me," and does nothing to help the parent.
To BlessedMom:
When you raise your children up, there is far more control over how they behave than once you catch them behaving. But this isn't a case of a parent asking how to raise their child to not do this, it is a case of finding their child is doing this.