I know that you can marry any character in Skyrim, regardless of their six and race,
Except for Khajiit, and Bosmer for some reason. :/
and I have to wonder what the offspring of some of these pairings would be like... assuming that they're interfertile, of course. We know that humans and elves and interbreed freely, but it's kind of ambiguous about orcs, carpets, and lizards.
Humans, and Elves interbreed with Khajiit, Orcs, and Argonians.
In Oblivion an Imperial Vampire mated with an Orc maid who gave birth to a Orc who was part vampire.
I think the general rule in TES is any, or almost any two races can get together, but the child will be born the same race as the mother.