Bagpuss
Legend
Which doesn't matter when it comes to making hybrids. If a PC wants to play a dwarf/dragonborn, it doesn't matter if magic was involved in the conception or not. The result is the same.
So the whole "this combo is off limits because they can't breed naturally" is a non-issue. Magic trumps it. Next.
Well you can read it two ways, one the DM doesn't need to allow any hybrids, unless they want to. But also any hybrid combo is possible, if you like so don't feel restricted to just mixing humans with orcs and elves.