About 4 in 10 never–married U.S. teenagers aged 15 to 19 have had sexual intercourse at least once, a new report reveals. The figure has not changed significantly since 2002, when the same survey was last conducted.

Most parents, however, don't think their teens are the ones having sex, a separate study last month found.

The new data, from the National Survey of Family Growth, was presented this week by the Centers for Disease Control and Prevention. 

The percent of never-married older teens (aged 18 and 19) who have had sex is about double that of younger teens (aged 15 to 17.)  Among females aged 15 to 17, about 28 percent said they had ever had sex compared with 60 percent for females aged 18 and 19.  For males, 29 percent of those aged 15 to 17 said they had ever had sex compared with 65 percent for those aged 18 and 19.

Other findings:

  • Among never–married teens, nearly 8 in 10 females (79 percent) and nearly 9 in 10 males (87 percent) used some form of contraception during their first sexual intercourse. For the most part, teens' use of contraceptives has changed little since 2002, and the condom remained the most commonly used method. 
  • From 2006 to 2008, 52 percent of never-married teen females and 71 percent of never-married teen males who had sex in the four weeks before the interview used a condom every time they had sex.
  • Less than half of never–married teen males (47 percent) reported they would be "very upset" if they got a partner pregnant, while 58 percent of never–married teen females said they would be very upset if they got pregnant.
  • Twenty–two percent of sexually experienced teen girls and 24 percent of sexually experienced teen boys said they would be "a little pleased" or "very pleased" if they were to get pregnant (or get a partner pregnant.)
  • The rhythm method, or use of periodic abstinence, increased in 2006–08, as 17 percent of teens reported having ever used this method, up from 11 percent in 2002.

About 71 percent of females and 64 percent of males said they "agree" or "strongly agree" that "it is okay for an unmarried female to have a child."  The percentage for males has increased sharply since 2002, when 50 percent said they agreed or strongly agreed with this question. The percentage for females has remained the same over that period of time.

The nationally representative results are based on 13,495 face-to-face interviews with those ages 15 to 44, including 2,767 teenagers (1,381 females and 1,386 males).