Yaoi

Supposedly related to the otome game genre.

The characters are typically very effeminate or beautiful and especially young. These are not guaranteed to be porn/eroge.

Yaoi is NOT supergroup for Japanese gay fiction, it's widely known/heard of but not the whole thing. Meaning things like bara are not sub-genres of yaoi.

The male lead characters usually epitomize common female values on desirable men (scientists have actually studied these!), which usually includes all of the following:
* Young (vague, somewhere around 15-25 range even if their actual age is different) and beautiful (capable of passing as females if they dress appropriately)
* Tall, lean, and toned body. Often on the boyish side of appearance.
* Shows a tender/emotional side
* Is wanted by many other characters (often both males and females)
* Is powerful, rich, or influential (and other people recognize this; possibly expansion of the above)
... all of which (except the last) also are almost mandatory parts of bishounen