From WebMD: "An estimated 90% of men who have sex with men and as many as 5% to 10% of sexually active women engage in receptive anal intercourse.
"While some people find anal sex enjoyable, the practice has downsides and requires special safety precautions."
Is Anal Sex Safe?
"There are a number of health risks with anal sex, and anal intercourse is the riskiest form of sexual activity for several reasons, including the following:
Anal Sex Safety and Health Concerns - webmd.com