Indeed, they are more responsible than adults about using condoms, the researchers report in a study coming out on Monday. A vast majority of sexually active 14- to 17-year-olds — 80 percent of boys and 69 percent of girls — said they had used a condom the last time they had intercourse, compared with well under half of adults involved in casual liaisons…

The study also found that while only about 7 percent of men and of women identified themselves as “other than heterosexual,” a much higher percentage reported having had sex with a member of the same sex. Among women in their 30s, for example, 14 percent said they had performed oral sex on another woman at some point in their lives; 13 percent of men over 40 said they had performed oral sex on another man.