Single-gender outsiders?

[Uncle Pine]

I was just thinking which outsiders can only be of a certain gender and which can be both male or female? Which have no gender and thus are unable to breed half-celestials/fiends?

I'm not an expert of outsiders' gender, but I think that any creature with acces to polymorph or similar could easily breed with any creature it change itself to. For example, I think gelatinous cubes are genderless, but you can easily make a half red dragon gelatinous cube.