Premarital Sex Isn’t New It turns out that your grandparents’ generation wasn’t as innocent as they led everyone to believe. Humans seem to be biologically hardwired for premarital sex. Surveys show that even among women born in the 1940s, supposedly a much more chaste era, more than 9 out of 10 had sex before getting married. When taking all generations from the 1940s through today into account, 95 percent of people have had sex before marriage at least once.