From RAINN:
http://www.rainn.org/statistics
*One in six women and one in thirty-three men will be sexually assaulted in their lifetime.
*Sexual Assault vs. Rape
Notice that we said "sexual assault," not "rape."
Sexual assault is a broader category that the Justice Department uses to classify rape, attempted rape, and other violent felonies that fall short of rape. Rape is defined as forced vaginal, oral, or anal penetration.
In 2005, there were approximately 200,780 sexual assaults. Of these, 64,080 were completed rapes. So if you want a figure that covers only rapes, divide 31,536,000 by 64,080. That comes out to 1 rape ever 492 seconds or 1 rape every 8 minutes.
*Breakdown by Gender and Age
Women
1 out of every 6 American women have been the victims of an attempted or completed rape in their lifetime (14.8% completed rape; 2.8% attempted rape).
17.7 million American women have been victims of attempted or completed rape.
9 of every 10 rape victims were female in 2003.
While about 80% of all victims are white, minorities are somewhat more likely to be attacked.
Lifetime rate of rape /attempted rape for women by race:
* All women: 17.6%
* White women: 17.7%
* Black women: 18.8%
* Asian Pacific Islander women: 6.8%
* American Indian/Alaskan women: 34.1%
* Mixed race women: 24.4%
Men
About 3% of American men — or 1 in 33 — have experienced an attempted or completed rape in their lifetime.
* In 2003, 1 in every ten rape victims were male.
* 2.78 million men in the U.S. have been victims of sexual assault or rape.
I couldn't find any stats on female-on-male rape. I'm not suggesting it never happens, just that the info isn't readily available.
ETA: The info on rape of males seems to point to male-on-male rape.
http://www.rainn.org/get-information/types-of-sexual-assault/male-sexual-assault