The majority of US rape victims are male.
No, really, ’tis true. There’s a small amount of the rape of men out in the general population: and the amount of rape in the prison population (a population which is overwhelmingly male) is larger than that in that general population.
Again, no, really. Despite the much smaller size of the prison population the number of rapes in it is larger (NOT just the percentage or the rate).
And thus the majority of rapes in the US are perpetrated upon men.
This generally isn’t true in other countries: much smaller prison populations and very much less rape in those that do exist.
Update: here’s a link to the stats.