Celem,
As I understand it, each caste needs to know how it reacts to its own caste, AND to each of the other castes. Therefore, a male caste needs one ORIENTATION tag for MALE:#:#:# (how does a male react to another male) and one ORIENTATION tag for FEMALE:#:#:# (how does a male react to a female), and the female caste needs equivalent tags (with a different sequence of numbers, obviously).
This is based on ToadyOne saying that the tag works as follows: [ORIENTATION:<caste>:<probability uninterested in stated caste>:<probability interested in lovers but not marriage with stated caste>:<probability interested in lovers-then-marriage with stated caste>] (paraphrased) according to his posts
here and
here. I believe that if a caste is missing one of the ORIENTATION tags (e.g. you only added custom numbers for [ORIENTATION:MALE] for females), the game uses the hidden default tag (you won't see it in the creature's raw entry unless you specifically want to change the numbers, in which case you "add" it in), so some females may still be homosexual/asexual.
Of course, my understanding may be wrong, given that I haven't been able to get my dwarves to act 100% heterosexually. Which is why I need to do some in-depth tests once I get back to my DF computer (this one runs at ~50FPS on embark in a pocket world, and drops to ~20 after the first migrant wave, by the first winter it's down to ~5FPS and completely unplayable from a testing standpoint, let alone a real fort).
The point of my previous post was to wonder if we can't add ORIENTATION tags for animals to see if that fixes the breeding issues (at the very least it would give us some more information), but to do that we first have to understand exactly how to make the tags work for dwarves.
-Dame de la Licorne
Edited for clarity.