What Does 'Had Sex' Mean? It Depends

Medical researchers sometimes want to know how a person's sex life affects their health. And it can affect how a doctor relates to a patient, such as when asking about partners of a patient who has a sexually transmitted infection.

But a study from the Kinsey Institute found that people have no common definition of what it means to have "had sex."

They said in a news release that they questioned 486 people from ages 18 to 96 who were meant to serve as a representative sample of the larger population.

About 30 percent of the people said that oral sex isn't sex. Twenty percent said the same about anal sex.

"Researchers, doctors, parents, sex educators should all be very careful and not assume that their own definition of sex is shared by the person they're talking to, be it a patient, a student, a child or study participant," said researcher Brandon Hill.

However, the study did not find large differences between what men and women consider sex.

The news release said that 95 percent of people agree that vaginal sex is sex. But some older men don't even count that, and 89 percent said it doesn't count if the man does not ejaculate.

The topic of anal sex had some variation. Overall, 81 percent said it is sex. But the rate was 77 percent for men 18 to 29, 50 percent for men older than 65 and 67 percent for women over 65.

The study was published in the international health journal Sexual Health.