Discussions of sex, while one of the most discussed human behaviours, are often superficial. Most ppl define abnormal sex as sexual behaviour they themselves do not want to engage in. Research by kinsey and masters, in the 40"s and 50s, revealed that masturbation, oral- genital sex, and homosexuality for example, were engaged in by far more ppl and w/ far greater frequency than was previously believed. Distress of the person suffering or causing harm to others. Prevalence in one study of 3000 adults, 43% of women and 31% of men reported occasional dysfns. By the time someone like joan consults a therapist, the prob has typically become more complex and involves secondary difficulties (ex// r"ship probs, low self-esteem) Dsm-5 focuses on 3 phases of potential dysfn: desire arousal orgasm. Each phase has subtypes of sexual dysfn: lifelong, acquired, generalize or sitn"l. Kaplan (1979) proposed an alt model consisting of desire, excitement, and orgasm.