The Art of Anal Intercourse dates back to ancient times suggests that the practice of anal sex stimulation of the anorectal area, including penile penetration has been around for many centuries. In fact, some might find it surprising how common a practice it is among heterosexual couples today. In one survey of 100,000 female readers of Redbook magazine, 43 percent of the women said they'd tried it with their partners at least once. Of that number, 40 percent said they found it somewhat or very enjoyable. (That is, about a quarter of the total number of women surveyed said this.) Forty-nine percent said they didn't care for it, and 10 percent said they had no strong feelings one way or the other. While not a controlled scientific study, this survey roughly parallels the findings of many other sexual surveys.

Something else that may come as a surprise to many: While a fair number of heterosexuals engage in the practice, not all homosexuals do. In a review of the existing data on the subject, the Kinsey Institute concluded that between 59 and 95 percent of male homosexuals had engaged in anal sex at least once.

In the age of AIDS, anal sex has received a lot of bad press and for good reason. Unprotected anal intercourse is the single most risky behavior in terms of exposure to the dreaded disease. It bears mentioning, however, that if neither you nor your partner is already infected with HIV (human immunodeficiency virus), you cannot get AIDS from anal sex. This may seem self-evident, but in a nationwide sex survey conducted by the Kinsey Institute, half of the American adults questioned said they thought you could get AIDS through anal intercourse, whether or not one partner was infected. This is simply not true.

What is true is that having anal intercourse with an infected partner, without using a condom, is the kind of sex behavior most likely to transmit AIDS. That's probably because the sensitive lining of the rectum is likely to tear during intercourse, allowing AIDS-infected blood or semen to pass directly into a sex partner's bloodstream. In fact, the evidence for this mode of AIDS transmission is so clear-and AIDS itself is so scary-that doctors now recommend against having anal sex with anybody, under any circumstances.