The latest report, published Thursday, is based on a nationally representative sample of about 4,100 teens. Eighty percent of them used contraception during their first sexual experience, it found.
Previous studies on teens' sexual attitudes and behavior also reveal how today's teens differ from older brothers and sisters as well as parents who grew up in the more permissive 1970s and '80s.
Teen pregnancy and birthrates have been falling since the early 1990s and reached a historic low in 2015. Public health experts credit a combination of widespread access to contraception, plus the decrease in the percentage of teens having sex.