http://en.wikipedia.org/wiki/Corrective_rape
Corrective rape is on the rise in South Africa. More than 10 lesbians are raped or gang-raped weekly, as estimated by Luleki Sizwe, a South African nonprofit.[22] It is estimated that at least 500 lesbians become victims of corrective rape every year and that 86% of black lesbians in the Western Cape live in fear of being sexually assaulted, as reported by the Triangle Project in 2008.[3] Yet, victims of corrective rape are less likely to report it because of the negative social view of homosexuality.[3] Under-reporting is high for sexually violent crimes, thus the number of corrective rapes are likely higher than what is reported.[3]
One South African man stated, "Lesbians get raped and killed because it is accepted by our community and by our culture".
In my world this is called genocide.