Well the most devastating one is chlamydia. 1.7 ,million women had it by 2018. Chlamydia will make a woman sterile, because it creates scaring on their fallopian tubes, so the egg cannot attach itself and thus it passes on without having a chance to get fertilized. Thus sterilization.
If 1.7 million women had it then, that meant that 1.7 women out of every 350 have it. That is not a low number. That is devastating to a society. It goes directly to the decline of birth rates in the country. Which is what we need to sustain our lives.
God is limiting our ability to sustain our race, so that we will be replaced.
The bigger issue of promiscuous sex is not so much the medical issue as is the consequences on not only your life but all those involved.
We do not think about the damage it creates not just for those involved but the secondary damages it creates for the extended families.
If we live in sin are we really happy. I suggest that people study the life of Solomon who lived about 900+/- BC. He was the wisest man, the richest man in the world.
His life is a study of what happiness is and is not. Read the book of Ecclesiastes and see what was true then which is true now.