Pleased to meet you.I am a male,happily married and committed, and look very much like my avi Uncle Lester.
When I lived in Oklahoma, 5 teenaged girls got busted for kidnapping and serial raping a teenaged boy classmate in a barn owned by one of the girls parents. They were convicted and did the time.
Once again, with feeling: rape is NOT a crime of passion, it is a crime of control through violence and intimidation. It is NOT an effective reproduction strategy, it goes against the standard model, which is also in current peril.
Though we most often tend to identify the crime of rape as one that is primarily an assault on women by men, as you have identified, women are quite capable of the atrocity as well. Same sex assaults or male-male and female-female prison rape are quite common and may be the least reported form of rape, according to some studies.
There is no single theory that conclusively explains the motivation for rape; the motives of rapists can be multi-factorial and are the subject of debate. Researchers have attempted to explain the motivation of a rapist in terms of socioeconomics, anger, power, sadism, sexual pleasure, psychopathy, ethical standards, attitudes toward women and evolutionary pressures. From Wiki
While I tend to agree that rape is less often a crime of sexual passion than one related to power and dominance, there are a number of contributing factors under study. I wonder how much the changing role of women in society is contributing to a sense of insecurity in some individuals, which may be translating into sexual aggression? That comment from a North American perspective, as in other parts of the world rape may have completely different motivation and bias.