Imagine, that in near future, there are several sexually transferable diseases. All work the same as AIDS: Transferred by blood and/or sperm. Deadly and no cure is found.
Also, humankind progressed in reproduction: If people want to have babies, they give their genetic material, which is cleaned from diseases (or simply put, you can always pick just sperm without any virus), selected the best candidates to produce offspring and such fetus is grown in controlled artificial uterus which provides the fetus perfect mixture of hormones and supports it to its full potential.
Lets assume this technology is relatively cheap and is provided to third world countries for free as humanitarian support.
We can assume there were several religious outbreaks against such technology, but right now, we are in point where all major religions accepted such technology, simply out of necessity (we are five generations into having such technology and people still want to believe into something)
During the time having this breeding technology, also technology for having safe sex was developed and works like Oculus Rift connected to your brain: You connect yourselves and your partner (not necessary in same place) and this technology stimulates your pleasure centers to provide you the most perfect orgasm you ever had.
This sexual technology is now wide spread and fairly accessible at the same level as breeding technology.
Given all this assumption, will people end with having physical sex? (Not necessary everyone but amount of people not having physical sex should be above 90%)
And if I add information, that condom is pretty safe low tech accessory to prevent you from new diseases?