White adolescent participants in the ADD Health Study were asked: "Have you ever had sexual intercourse? When we say sexual intercourse, we mean when a male inserts his penis into a female's vagina."
Here are the percentages who answered yes by religious affiliation (sample size = 4,180, mean age is 15.0):
Percent of teens who have had sex
No religion 47.1*
Disciples of Christ 31.6
* significantly higher than Mormons
Those with no religion are most likely to report sexual intercourse. Compared to Mormons, their rate is 2.2 times higher.