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
Sex differences in medicine as evidence increases that the symptoms and responses to medical treatment may be very different between sexes. Sex-related illnesses have various causes: Examples of sex-related illnesses and disorders in female humans: Examples of sex-related illnesses and disorders in male humans: Sex differences in medicine Sex differences in medicine include sex-specific diseases or conditions which occur "only" in people of one sex (for example, prostate cancer in males or uterine cancer in females); sex-related diseases, which are diseases that are more common to one sex (for example, systemic lupus erythematosus occurs predominantly in females); and diseases which occur at similar rates