fun fact! They never specify that dads are human!

So their dads are other horsegirls 🤔 The other, worse option isn't an option because there are no horses in the world

They don't say HOW any of them are born right??? I like to think that it's like, a random chance that your unborn child will be possessed by the spirit of a race horse and that's how umas are born, kinda like having three parents???

That definitely does seem to be what happens sometimes, but other times, Umamusume give birth to other Umamusume (for example, Special Week's mother is shown to be an Umamusume)

Ah and I bet they "breed true" by that point :P