werewolf the apocalypse – On Werewolves and Hybrid Metis

I’m the secondary storyteller for a Werewolf: The Apocalypse game.

Our group is made out of mostly urban figures – specially Glass Walkers and Bone Gnawlers – playing out a very finance-oriented pack that is trying to do their part in saving Gaia by playing the Corporate Game/Stock Market and using their money and influence to change the world.

Yes, I have a weird group. Anyway!

A new player is scheduled to join the ranks of our pack. They want to play as a Metis, but of a non-standard type: a Ratkin/Garou hybrid Metis.

While mechanically this is easy to achieve – just put them to play by Garou rules and add a few appropriate Merits/Flaws – I have no idea if this is actually something that can be achieved lore-wise.

Is it possible to have a Metis born of parents of different Changing Breeds? If so, what happens? Is the Metis an hybrid, or does it take the after only one parent?