The women's movement of the 1960s spawned the anti-rape movement which incited change in the legal arena and was the first time that acquaintance rape was identified and studied. Rape crisis centers, marches, speak outs, and feminist organizations, challenged the public's ideology regarding the definitions as well as the prevalence of the act of rape. New laws have been formed such as the federal Violence Against Women Act in 1994 which provides for law enforcement and prosecution grants to assist states to develop and strengthen effective law enforcement and prosecution strategies and victim services in cases involving violent crimes against women.
There are two primary theories and assumptions as to why a sexual offenders commit sexual violence or assault. Offender-related theories suggest that factors at the individual level contribute to the likelihood of a person committing sexually violent acts. These range from biological factors such as evolution, physiology, substance abuse, and psychopathology. Societal-influence theories suggests that environmental factors such as attitude and social learning contribute to the occurrence of sexual violence.
The offender-related theory of evolution states that the differences between men and women in current human mating patterns may be the result of strategies that created reproductive success among our human ancestors. This theory is not accepted by most researchers and does not address the large number of assaults lacking reproductive consequences because they involve oral or anal penetration or victims who are prepubescent or male. Evolution alone cannot account for sexual assault or intimate partner violence.
Another assumption in the offender-related theory is that Physiology and Neurophysiology traits such as hormones, chemicals in the body, head traumas, or brain abnormalities can cause offenders to be sexually violent. There is a correlation between testosterone levels in humans and aggression, but it is not clear whether testosterone levels lead to aggressive behavior or rise as a result of aggressive behavior.
