Headscratchers / Of Mice and Mayhem

• One of the big conflicts of the story is that Chip doesn't push forward his relationship with Gadget because they're genetically incompatible species, and he respects the idea she may want to have a family some day. Gadget discovering the events of "A Fly In The Ointment" left her genetically compatible with chipmunks resolves this problem, clearing the way for their relationship to move forward. But was this really necessary? Does the Mouse World have no such thing as adoption? Even humans have relationships that are not conducive to biological offspring (same-sex marriages, or where one partner is medically incapable of having children) that are still able to have children through other methods (adoption, surrogacy, artificial insemination, etc.) so it's not like there weren't other possible solutions that Chip could have considered.