The development of sexuality and eroticism in humankind.

Sexuality includes eroticism. Though its determinants are multivariate and developmentally sequential, most current biological theories arbitrarily exclude social determinants, and vice versa. Developmentally, masculinization is not necessarily synonymous with defeminization, nor feminization with demasculinization. In the development of brain and behavior, behavior that appears to be either male or female may actually be sex-shared but sex-different in the threshold for its expression. Parent-child bonding is a precursor of subsequent erotosexual pair-bonding. Suppression of erotosexual rehearsal play in childhood is a precursor of postpubertal and adult erotosexual pathology. The criterion defining the heterosexual, bisexual, and homosexual conditions is the sex of the partner with whom a limerent (falling-in-love) pairbond is possible; and there is no evidence that pubertal sex steroids, per se, are responsible for which of the three it will be. The phases of an erotosexual encounter are proception, acception, and conception. The disorders of proception, manifested in both imagery and practice, are the paraphilic syndromes (formerly known as perversions). The disorders of acception may be either hypophilic deficiencies, or hyperphilic increases. The disorders of conception are those of infertility. There is a nonsystematic relationship of erotosexualism to the hormonal cycle of the menses and to gerontological hormonal changes.