Board Thread:Speculation House/@comment-17760348-20131021233145/@comment-24144063-20140407234005

I think his point was that maybe humans and faunus are incapable of interbreeding, not simply unwilling. They may look outwardly similar, but it's possible that genetically they could be incompatable. That doesn't mean relationships can't form between humans and faunus, just that they wouldn't be able to have children.