I know that Tieflings and Aasimar can mate and have offspring with Gnomes. I know that most races native to Golarian (human, elf, dwarf, etc.) can't. Purely for flavor, I'm creating a Gnome academic of some standing who has -- for the novelty and to further her learning -- sought out partners of as many races as possible and had children by them. I'm imagining a large family with siblings who're half gnome and half (devil, demon, azata, garuda, djinn, efreet, etc.)
So...what races do we know can(n't) mix successfully with gnomes?