NEW YORK - The male-female orgasm gap. The sex lives of 14-year-olds. An intriguing breakdown of condom usage rates, by age and ethnicity, with teens emerging as more safe-sex-conscious than boomers.
That's just a tiny sampling of the data unveiled Monday in what the researchers say is the largest, most comprehensive national survey of Americans' sexual behavior since 1994.
The study, by researchers from the Center for Sexual Health Promotion at Indiana University, surveyed 5,865 people aged 14 to 94 about their sexual activities, profiling what sex acts they engaged in, and what precautions they took. The researchers wrote Americans have become more experimental in the 16 years since a report published by the University of Chicago in 1994.
Compared with that study, "more men and women have engaged in oral sex and a significantly greater proportion have engaged in anal sex," the study says.
About 40 percent of women ages 20 to 49 and of men ages 25 to 59 have engaged in anal sex, the study found. More than 80 percent of women aged 20 through 49, and more than 85 percent of men in that group had received oral sex, the study found.
While Americans are bombarded with sexual imagery, they have little access to reliable information about sexual behavior, said Monica Rodriguez, president of the Sexuality Information and Education Council of the United States, a nonprofit in New York. "That's why this is so important - it gives us a sense of what's really happening, instead of all this, 'Well, my sex life must not be normal, because I don't do this or only do this.'"
The researchers said they were struck by the variety of ways in which the subjects had sex - 41 combinations of sex acts were tallied, including vaginal and anal intercourse, oral sex, and partnered masturbation.
Men are more likely to reach orgasm when vaginal intercourse is involved, while women are more likely to reach orgasm when they engage in variety of acts, including oral sex, said Debra Herbenick, lead author of the section about women's sex lives.
She noted a perception gap - 85 percent of the men said their latest sex partner had an orgasm, while only 64 percent of the women reported having orgasm in their most recent sexual event.
The difference can't be accounted for by men having male partners, said Pepper Schwartz, a professor at the University of Washington in Seattle who wasn't involved in the survey. It's probably because of poor communication between the genders, she said by phone.
The maker of Trojan condoms funded the study. Questions about condom usage figured prominently in the study, but the researchers - during a teleconference - insisted the integrity of their findings' was not affected.
A high rate of condom usage among 14 to 17-year-olds was among the findings. Of the surveyed boys who had sexual intercourse, 79 percent reported using a condom on the most recent occasion, compared to 25 percent for the survey's men.
Another finding: Rates of condom usage among black and Hispanic men were significantly higher than for whites. The researchers said this suggested that HIV-AIDS awareness programs were making headway in those communities, which have relatively high rates of the disease.
Most worrisome, the researchers said, was that the lowest condom usage rates were for men over 50. Although men in that group are more likely to be married than males in their teens and 20s, other surveys have shown 50s-plus to be far more open to multiple sexual partners, raising the risk for disease.
Other notable findings:
•While about 7 percent of women and 8 percent of men identify as gay, lesbian, or bisexual, the proportion of people who have had same-gender sex at some point in their lives is higher. For example, 15 percent of men aged 50-59 said they had received oral sex from another man at some point.
•Women over 50 were more likely to reach orgasm during sex with a casual or new acquaintance rather than a relationship partner; 81 percent reported orgasm with a nonrelationship partner to 58 percent reporting an with a relationship sex partner. This may be because a partner is less likely to engage in romance, flattery, and attention, Ms. Schwartz said.
•Among adolescent boys, only about 2 percent of the 14-year-olds and 40 percent of the 17-year-olds said they had engaged in sexual intercourse in the past year.