The vast majority of Americans have sex before marriage, including those who abstained from sex during their teenage years, according to "Trends in Premarital Sex in the United States, 1954–2003," by Lawrence B. Finer, published in the January/February 2007 issue of Public Health Reports. Further, contrary to the public perception that premarital sex is much more common now than in the past, the study shows that even among women who were born in the 1940s, nearly nine in 10 had sex before marriage.

The new study uses data from several rounds of the federal National Survey of Family Growth to examine sexual behavior before marriage, and how it has changed over time. According to the analysis, by age 44, 99% of respondents had had sex, and 95% had done so before marriage. Even among those who abstained from sex until age 20 or older, 81% had had premarital sex by age 44.

"This is reality-check research. Premarital sex is normal behavior for the vast majority of Americans, and has been for decades," says study author Lawrence Finer, director of domestic research at the Guttmacher Institute. "The data clearly show that the majority of older teens and adults have already had sex before marriage, which calls into question the federal government’s funding of abstinence-only-until-marriage programs for 12–29-year-olds. It would be more effective to provide young people with the skills and information they need to be safe once they become sexually active—which nearly everyone eventually will."

Indeed, while the likelihood that Americans will have sex before marriage has remained virtually unchanged since the 1950s, people now wait longer to get married, so they are sexually active and unmarried for much longer than in the past. During this period, Dr. Finer concludes, young adults have an especially great need for accurate information about how to protect themselves against unintended pregnancies and sexually transmitted infections.