Just watched the Tiefling video on @DnDBeyond . I’m curious, are tieflings and aasimar in the Forgotten Realms like half-elves or half orcs in that they occur from genetics of a parent? Could two human parents have a tiefling child? it's a reflection of their magical nature, a soul imbued with power that is reflected in its physical form. two humans might have a tiefling child if they had some tie to the Nine Hells

— Mike Mearls (@mikemearls) January 12, 2018