Board Thread:General Discussion/@comment-173.20.10.245-20131101064024/@comment-16502426-20140731011026

Moreover, the only reasons separate species cannot breed in real life is because of either physical or genetic incompatibility. Humans and Faunus seem to be physically identical other than a few small differences, which certainly wouldn't be enough to prevent breeding. They also logically are at the very worst a recent split between them, speaking evolutionarily, so they're likely even more genetically similar than most examples on Earth.

At the very least, they can successfully breed, and I doubt the offspring are sterile, since even on Earth that is not always the case. There are a huge number of wildcats, for example, that can produce healthy, non-sterile offspring when bred with domestic cats.