Sex means a lot of different things apparently.If one of your friends is bragging that she "had sex" with some guy, bear in mind you might actually not have any idea what she's talking about before you give her a high-five.

According to new research from the Kinsey Institute, nobody can agree on what "sex" actually means. A representative sample of men and women age 18–96 was asked whether the fact that a man was wearing a condom, or a woman had an orgasm, determined whether an act was sex or not sex. There was no consensus.

Gender did not matter much, but age seemed to make a big difference. For instance, only 77 percent of men age 65 and older would define penile-vaginal congress as "sex." (Really? What would you call it, Old People?)

Overall: 95 percent of respondents define sex as intercourse, but only when there's ejaculation. (If a guy doesn't get off, only 89 percent believe it's real, live nookie.) 81 percent considered anal sex intercourse. And an average of 72 percent of men and women considered giving or receiving oral sex "sex."

So maybe the next time you ask somebody how many partners he's had, you might also want to ask exactly what his idea of sex entails. Even if he's 96 and should really know better.