From the Amnesty International website:
Gender-based violence stems from the failure of governments and societies to recognize the human rights of women. It is rooted in a global culture of discrimination which denies women equal rights with men and which legitimizes the appropriation of women’s bodies for individual gratification or political ends. Everyday, all over the world, women face gender-specific persecution including genital mutilation, sexual slavery, forced prostitution, and domestic violence. At least one out of every three women worldwide has been beaten, coerced into sex, or otherwise abused in her lifetime.
Wonderful website with lots of ways to get involved.
For more information, see Amnesty International.