It seems S.T.I.s are one of the last taboos.

(Incidentally, some people — including the C.D.C. — still use the term “sexually transmitted diseases.” However, “sexually transmitted infectious diseases” and “sexually transmitted infections” are also considered acceptable. I feel the word “disease” in this context sounds stigmatizing, which is why I don’t use it.)

I don’t need to tell you that we live in an era of easy access to sex: Pornography is a click away and often free. Full frontal nudity and graphically simulated sex scenes are part of many television shows and movies. Popular magazines for women have explicit articles on fellatio and anal sex. People are very specific on dating apps about looking for hookups.

I want to be very clear that none of this is wrong. You like what you like, whether that is how you choose to be entertained, your fantasies or the way you engage sexually. If it’s all consensual, it’s all good.

We are also able to talk more publicly about other aspects of sex, like contraception choices and abortion (#ShoutYourAbortion is one of many hashtags). And yet there seems to be a hard line at S.T.I.s.

What makes this especially surprising is that S.T.I.s are so ubiquitous. Consider that 50 percent of sexually active people will have at least one S.T.I. by age 25 (HPV is the most common) and there are over 110 million new and existing S.T.I. cases each year in the United States. People are clearly not shy sharing with me, so the only logical conclusion is the sexual revolution stopped short of liberating people from the shame and stigma of sexually transmitted infections.