The synthesized theory is based on four propositions: (1) two drives, the sex drive and the drive to possess and control, motivate rape; (2) as a result of natural selection, the average sex drive of men is stronger than that of women; (3) although the motivation for sexual assault is essentially unlearned, the behavior surrounding sexual assault is learned, and the major form of learning is experiential rather than imitative or attitudinal; and (4) because of variations in exposure of the brain to male-typical sex hormone regimens, individuals differ in their sex drives and in their sensitivity to the threat of punishment and to the suffering of others. The synthesized theory draws on the strengths and weaknesses of rape theories of the 1970's and suggests how elements from each theory can be united under a new theory. In addition, the synthesized theory incorporates knowledge of how sex hormones alter brain functioning. In general, the theory contends that, quite apart from differential social experiences, people are not all equally prone toward rape. 153 references and 1 figure (Author abstract modified)