The incidence of this complaint remains unknown. First, there is the unwarranted assumption that the sexual response cycle unfolds in phases, and that each phase may be diagnosed independently of another. Additionally, there is the assumption of linearity and parallel processes for men and women. The DSM-IV diagnostic system describes a smooth linear progression of sexual behavior from desire to arousal to orgasm. As noted, there is a high degree of overlap between disorders.
Most disorders tend to co-occur and to occur on a continuum of mild to moderate to severe.
Objective, operational definitions of both male and female sexual disorders do not exist, and diagnosis tends to be rather imprecise and global. The recognition and legitimization of personal distress as an essential ingredient of diagnosis is very important because it acknowledges and validates the subjective nature of sexual problems. Nonetheless, there is little doubt that both male and female sexual difficulties detract from emotional and relationship satisfaction and can diminish quality of life. A number of biological factors, including gender, age, hormone levels, depression, cardiovascular disease, diabetes, alcohol abuse, medications, and general poor health, serve as predictors of sexual dysfunction. As has been noted, women have nearly twice the number of sexual problems as do men.