Animal sexual behaviour however, is proving to be false as, "most hormones don’t influence behaviour directly. Rather, they affect thinking and emotions in variable ways (Azar, 40)." There is much more involved in sexual behaviour in the mammalian animal than oxytocin and vasopressin can explain. It is often assumed that animals do not have sex for pleasure, or alternatively that humans, pigs, bonoboes (and perhaps dolphins and one or two more species of primates) are the only species that do. This is sometimes stated as "animals mate only for reproduction". This view is considered a misconception by some scholars. Jonathan Balcombe argues that
Men who have sex with men are more likely to break during anal sex than during vaginal sex. Thus, even with a condom, anal sex can be risky. Acquired immune deficiency syndrome (AIDS) is a disease of the human immune system caused by the human immunodeficiency virus (HIV). HIV can infect anybody, regardless of sex, ethnicity, or sexual orientation. Worldwide, an estimated 5–10% of HIV infections are the result of men having sex with men. However, in many developed countries, more HIV infections are transmitted by men having sex with men than by any other transmission route. In the United States, "men who have had sex