In the largest study of its kind in the United Kingdom, researchers found 85 percent of the 1,200 lesbian and bisexual woman surveyed have had sex with men, reports HealthScoutNews. They found the women at community centres and sexual health clinics. The study appears in the April issue of Sexually Transmitted Infections.

While many of the women surveyed had sex with men during their lives, only 12 percent had done so within the past year and 70 percent had the last sexual encounter with a male at least four years ago.

Most of the women who said they had had sex with men during their lives revealed that their first sexual experience had been with a man, typically around age 18, then went on to sex with a woman three years later.

Susan Cochran, an expert on lesbian health and professor of epidemiology at the University of California at Los Angeles wasn't surprised at the findings. She said that American studies have shown similar results although the numbers are changing, as younger lesbians are less likely to report ever having had sex with men.

"That reflects more sexual freedom among women. They have more choices and more control over their sexuality," she said.

The survey was completed between 1992 and 1995.

Cochran said lesbians may have start off with having a heterosexual relationship in their lives - a phenomenon that's less common among gay men - because they don't always need to take the initiative.

"Young women are propositioned all the time for sex. Men typically initiate it and women say yes or they say no," she says. Young gay men, however, usually must initiate a relationship with a woman, and they may be less likely to take that more rigorous step.

Although the rate of STI transmission is relatively low among bisexual women and lesbians, experts expressed concern that women who think they face no risk of being infected with a sexually transmitted disease or HIV are wrong.

Writing in the medical journal, Sexually Transmitted Infections, Professor Adler, of the Royal Free and University College Medical School, London, paints a dismal picture of the nation's declining sexual health over the past decade.

Among the women surveyed, 20% of those sharing sex toys said they did not use condoms or clean them properly before sharing while over 85% of lesbians engaging in oral sex with other women did not use dental dams.

---

A third of the 328 women surveyed about safer sex practices, a third who had had penetrative sex with men had never used a condom.

Study co-author Dr. Julia Bailey, a researcher at London's King's College, says she hopes the research will encourage doctors to not make assumptions about the women they treat.

"If a woman tells you she's a lesbian or bisexual woman, this does not mean you know what she does (or doesn't do) in bed," she says. "Many lesbians engage in penetrative sex, have sex with men, get pregnant and have children."

Sex with men may put lesbians at risk of sexually transmitted diseases and unintended pregnancy, she says. Of those who reported intercourse with men, one-third said they never used condoms.

"Open discussion about these issues is needed so that lesbians can make informed choices," Bailey says.

Researchers also studied the variety of sexual practices that lesbians engage in with each other. Ninety-seven percent reported engaging in oral sex often or occasionally. Other popular activities included vaginal penetration with fingers (97 percent), mutual masturbation (95 percent), anal penetration with fingers (55 percent) and vaginal penetration with sex toys (53 percent).

In one of the most surprising findings, one in four lesbians said they had been pregnant, as had 29 percent of bisexual women.

The survey also showed that the average number of sexual partners in the preceding year was one.