Rape by gender

This article classifies types of rape by the sex of both the rapist and the victim. The scope of the article includes both rape and sexual violence more generally.

Since only a small percentage of acts of sexual violence are brought to the attention of the authorities, it is impossible to compile accurate statistics. There are nevertheless statistical estimates published by some official bodies. The U.S. Bureau of Justice Statistics (1997) estimated that 91% of United States rape victims were female and 9% were male, with 99% of the offenders being male and 1% of the offenders being female. Several studies argue that male-male and female-female prison rape are quite common and may be the least reported form of rape.

Rape of females by males
In a 2000 research article from the Home Office, in England and Wales, around 1 in 20 women (5%) said that they had been raped at some point in their life from the age of 16 beyond.

In 2011 the US Centers for Disease Control found that "nearly 20% of all women" suffered rape or attempted rape sometime in their life. More than a third of the victims were raped before the age of 18.

A woman's physiological response to sexual contact is involuntary. In some cases, women can become physically aroused, produce natural lubrication, and even experience orgasms against their will during rape. . One proposed explanation for this genital arousal in some women is that it acts as a preparatory mechanism which served in the past to protect women from genital injury during unwanted sex. . This is in line with previous research showing that many women show vaginal lubrication when exposed to a broad array of sexual stimuli (even that involving chimps) regardless of stated preferences and subjective feelings.

Pregnancy may result from rape. The rate varies between settings and depends particularly on the extent to which non-barrier contraceptives are being used. A study of adolescents in Ethiopia found that among those who reported being raped, 17% became pregnant after the rape, a figure which is similar to the 15–18% reported by rape crisis centres in Mexico. A longitudinal study in the United States of over 4000 women followed for 3 years found that the national rape related pregnancy rate was 5.0% per rape among victims aged 12–45 years, producing over 32,000 pregnancies nationally among women from rape each year. Experience of coerced sex at an early age reduces a woman’s ability to see her sexuality as something over which she has control.

Rape of males by males
Several studies argue that male-male prisoner rape, as well as female-female prisoner rape, might be the most common and least-reported forms of rape, with some studies suggesting such rapes are substantially more common in both per-capita and raw-number totals than male-female rapes in the general population.

Research from the UK suggests that almost 3% of men reported a non-consensual sexual experience as adults and over 5% of men reported sexual abuse as a child. This does not take into account the possibility of exaggeration or false reports nor of underreporting. Recognition of male on male rape in law has historically been limited; the first successful prosecution for attempted male on male rape in the UK was not until 1995.

Male on male rape has historically been shrouded in secrecy due to the stigma men associate with being raped by other men. According to psychologist Dr Sarah Crome fewer than one in ten male-male rapes are reported. As a group, male rape victims reported a lack of services and support, and legal systems are often ill-equipped to deal with this type of crime.

The rape of men by men has been documented as a weapon of terror in warfare.

Rape of males by females
Women also can commit an act of rape with force or deception to make a man engage in a non-consensual penetrative sexual act.

Statutory female-on-male rape
Several widely publicized cases of female-on-male statutory rape in the United States involved school teachers raping their underage students. (See e.g. Mary Kay Letourneau or Debra Lafave)

Non-statutory female-on-male rape
Much like female erectile response and contrary to popular opinion, male erectile response is involuntary, meaning that a man need not consent for his penis to become erect and be placed in a woman's vagina. Penetration of a man by a woman is possible through use of a strap-on or other object. Rape of a man by a woman could also occur when limited sexual activities are agreed upon and a man's penis is placed in a woman in violation of the limits that had been set. Rape of a man by a woman is thus possible in several ways.

However, male victims of sexual abuse by females often face social, political, and legal double standards. While gender-neutral laws have combated the older perception that rape never occurs to men, and other laws have eliminated the term altogether, the double standards still remain.

Rape of females by females
Female-on-female rape is often labeled "lesbian rape", though the sexual orientation of one or both (or more) persons involved may or may not actually be lesbian. Assault by forcible stimulation of external sexual female genitalia or forced penetration by another woman is possible with the use of strap-ons, dildos, other foreign objects which could include a tongue (inserted or external) in forced oral, forced digit manipulation (in masturbation by force) and digital penetration.

A few books, such as Violent Betrayal: Partner Abuse in Lesbian Relationships by Dr. Claire M. Renzetti, No More Secrets: Violence in Lesbian Relationships by Janice Ristock, and Woman-to-Woman Sexual Violence: Does She Call It Rape? by Lori B. Girshick also cover the topic of rape of women by other women.