David Wayne on statistics that indicate that evangelical teenagers, despite a pronounced ethic against premarital sex, are just as likely to engage in it:
In fact, there is evidence that evangelical teenagers on the whole may be more immoral than non-Christians. Statistically, evangelical teens tend to have sex first at a younger age, 16.3, compared to liberal Protestants, who tend to lose their virginity at 16.7. And young evangelicals are far more likely to have had three or more sexual partners (13.7 percent) than non-evangelicals.
As previously noted, we have to be careful of statistics casually thrown about. But Wayne brings up a critical point that helps explain why evangelical Christians are engaging in premarital sex:
And the bible does offer a direct solution for people who are burning in lust (I Corintihans 7:9). Adolescence - that time when a person is physically an adult but socially a child - is a modern invention. In the past, people married much younger, as soon as they were sexually ready. Today's culture postpones marriage while stretching celibacy to the breaking point.
A counter-cultural church may do well to encourage younger marriages. . . .
Possibly, although the age of first marriage (in America, at least) has not risen that much over time.