I'll try to explain:
1. Teen sex is not a sin - early civilization had girls wedding in their early teens. When did it become a sin?
2. Premarital sex is a sin - It is taught in the New Testament.
3. Birth control is not a sin - I cannot find anywhere in the Old or New Testament where it says "Thou Shall Not Use Birth Control". This is a church teaching and the church has been known to be wrong. Look at the Catholic Church in the Middle Ages.
I didn't say teen sex was a sin, and until the 1900's marriage in American states ranged from 10 to 12 but progressives/reformers got it raised because it was said to cause prostitution.
If premarital sex is a sin and many if not most abortions are a result of it then shouldn't that be addressed instead of excusing the sex part? You said solutions don't mean giving in but haven't most religious people given in on sins like adultery and fornication that feed our systems.
Again I didn't say birth control was a sin, as for the Catholic Church in the middle ages why stop there?