I was preaching and teaching that in the early 1980s - not that people in my church wanted to hear it.
If there are any people who should have a positive understanding and attitude toward sex, it is Christians.
That in no way implies permissiveness; it simply means that God designed it, and it is good.
It is powerful, and sin makes it potentially very destructive, but it is not “dirty” as so many Churchians (as I call them) think and say.
When I was in youth ministry, fornication was, no surprise, a problem - precisely because no one wanted to talk about sex.
My recurring message to young people was: So, you really, really like doing it, but you think talking about it respectfully is dirty.
My background is both in biology and theology, so I had no problem discussing it respectfully and without embarrassment. As I often said, when quoting a Bible passage explicitly dealing with sex, “God is not shy talking about it; why are we?”
(I, a chaste single male and Bible teacher, was denounced as indecent for that by the worst fornicators in the youth group.)
I imagine there were other reasons as well.