This study is fascinating — more than 90 percent of Americans have premarital sex, even going back to those born in the 1940s.

Bear in mind the biases of the researchers:

“Finer is a research director at the Guttmacher Institute, a private New York-based think tank that studies sexual and reproductive issues and which disagrees with government-funded programs that rely primarily on abstinence-only teachings.”

I’m skeptical of the study for a few reasons. For one, it found that 80 percent of those who abstained until age 20 still had sex before they got married, which strikes me as maybe a llittle high. 60 percent of students are active before graduating high school, so I’d think many of the abstainers kept zipped for a reason.

But I’m most skeptical of the implications people are taking from it. For example, the news stories say this challenges “perceptions that people were more chaste in the past.”

Well, not really. It only goes back to people born in the 1940s — even the oldest ones turned 20 in 1960, the dawn of a decade not know for its sexual repression. That was the very year the birth control pill was introduced.

When people say chastity used to be more common, they’re typically referring to the 1950s and earlier. You’d need folks born in the early ’40s and before, not people dating back to the 1940s generally, to test that.

I also think there are more important things than the sex-no sex dichotomy measures. For example, people married earlier in the past, so they would have fewer years in which to fool around. This means fewer sex partners; less promiscuity if not more chastity. Also, before the birth control pill people got married to cover up pregnancies — that’s why illegitimate birth was so rare then.

The research makes no attempt to distinguish between someone who loses his/her virginity to a fiancee and someone who starts sleeping around at 16. Both are “premarital sex,” and I’d guess the latter got a lot more frequent after the pill and Roe v. Wade.

The research, if done correctly, does indicate that abstinence programs aren’t likely to succeed in today’s world (and lest the above make it sound otherwise, I think the birth control pill is a good technological development). But it doesn’t say that sexual mores and behaviors haven’t changed for the worse in the last few decades, and the results need to been seen in the context of skyrocketed illegitimacy.

Robert VerBruggen blogs at http://www.therationale.com and http://robertsrationale.blogspot.com.