This is an expansion of
Ebbixx's point about universality. I have read (possibly in books by
Poitras,
Levy,
Napier),(but have yet to see) that there are many quite
explicit homosexual
anime and
manga whose
target audience is female, and that this practice is considered entirely normal. I am no expert on
Japan or
Japanese culture, but this example definitely points toward a lack of universality on a cultural level.
Perhaps this fits with lioncub's argument that women may not be turned on by gay porn because there is no hope of joining in. cartoons are imaginary people who are neither gay nor straight in "real life", and as long as the viewer suspends their disbelief far enough to be turned on by animation, this difficulty of imagining oneself into the sex disappears.