Q: Dear Sage,
If a half-elf mates with a human, what race would the child be? What about other half-humanoid races?
A: While the most common origin of a half-elf mentioned in the Player’s Handbook is a union between a human and an elf, it also mentions that “second-generation” half elves are possible—“the children of parents who themselves are partly human and partly elf” (PHB, pg. 18). The Sage thinks it reasonable to conclude that any half-elf parent is capable of parenting a half-elf child when mating with a human (or with an elf, for that matter).
Similar language doesn’t appear in the half-orc description, but it seems a reasonable extrapolation for that and other, similar races. Two half-orcs likely have half-orc children, and a half-orc mating with either a human or an orc probably also generates half-orc offspring.
Of course, the DM is free to rule that one side or the other occasionally breeds true—that two half-elves might have an elf child or a human child, for example.
About the Author
The Sage is a mammal classified in the bear family, Ursidae, native to central and southern China. Debate continues as to whether he is truly a bear or more related to the raccoon rather than the bear, or perhaps in a family of his own. When not eating bamboo and answering rules questions, he works under the nom de plume of Andy Collins as an RPG developer in Wizards of the Coast R&D, where his development credits include Complete Mage, Dragon Magic, and the Player's Handbook v.3.5. He can be easily recognized by his large, distinctive black patches around the eyes, ears and on his rotund body.