This article originally appeared on Time.com.
Teenagers and young adults are engaging in a wider variety of sexual practices than they did 20 years ago, according to a new study in the Journal of Adolescent Health. Among sexually active heterosexual young people surveyed for the study, the percentage who said they’d had vaginal, oral and anal sex during the last year more than doubled between 1990 and 2012.
The researchers analyzed more than 45,000 interviews from three surveys of British residents ages 16 to 24, conducted every decade. The people interviewed in the first survey were born in the 1930s, while those in the most recent survey were born between in the 1990s.
In all three surveys over the 22-year period, vaginal sex was the most common sexual practice. But the percentages of sexually active people who also reported having had oral and anal sex in the last year increased over time, from 1 in 10 people in 1990-1991 to 1 in 4 men, and 1 in 5 women, in 2010-2012.
Between the first and second decade, that increase was most notable among 19- to 24-year-olds. But between the second and third, the increase was larger among 16- to 19-year-olds—suggesting that these trends have “filtered down the age range over time,” the authors wrote in their analysis.
Modest declines in vaginal intercourse and genital-to-genital contact were also observed over the study period. But for the most part, the authors wrote, “we are seeing oral and anal sex joining, rather than replacing, vaginal intercourse in heterosexual repertoires.” Previous studies have suggested similar trends in other high-income countries, and the authors say their findings could potentially apply to young Americans as well.
The surveys also asked people about same-sex experiences, but the number of people who reported engaging in these was not large enough to perform a meaningful analysis of trends for homosexual activity, the authors say.
Because the study relied on self-reported data, the authors acknowledge that they may not have the whole story. As society has become more accepting of different types of sex, they say, people may have been more likely to respond honestly about their own practices. They also note that the last survey was conducted in 2012 and that sexual practices may have continued to shift since then.
But if the responses really are evidence of changing behaviors, they could also present potential risks. Research has shown, for example, that teenagers—especially girls—can feel pressured to engage in oral or anal sex, even when they find it painful or unpleasant. Studies have also found that couples are less likely to use condoms when they engage in anal sex, as opposed to vaginal intercourse.
Eli Coleman, professor and director of the program in human sexuality at the University of Minnesota medical school, says that teens and young adults need more education about the risks of sexually transmitted infections (STIs), especially if they’re engaging in practices other than vaginal sex. “Teenagers are incredibly concerned about preventing pregnancy, and they’re doing a better job of that,” says Coleman, who was not involved in the new study. “But they are not concerned enough about STIs and their potential long-term consequences.” Coleman cites increases in chlamydia and drug-resistant gonorrhea in recent years, and says that sex education needs to start early—before kids become sexually active.
The British research also suggests that the age at which people have their first sexual experience, like kissing or intimate touching, is getting younger: from 16 in the earliest survey group to 14 in the most recent. The age at which people are first having sexual intercourse (oral, vaginal or anal) also decreased, from age 20 for women and 19 for men in the 1990s to 16 for both men and women in the 2010s.
That might not be the case in the United States, however. The teenage pregnancy rate is at an all-time low in the U.S., and another study recently found that American teens today are having less sex than those in generations before them.
As for the reported increase in anal sex, the authors note that access to pornography is often cited as a potential driving factor. But they caution against attributing this trend to any one thing, as it’s likely due to a “complex socio-sexual landscape” of which porn is just one element. They also point out that the overall number of people who said they engaged in anal sex was still small, even in the most recent study.
Regardless of what’s behind these trends, keeping pace with them is important to making sure that health information reflects what young people are actually doing. “We should be concerned about all aspects of sexual health and promote honesty and communication in relationships, and not just worry about the adverse outcomes,” Coleman says. “We need to promote ways people can explore their sexuality in a healthy, responsible manner.”