Board Thread:Lore Discussion/@comment-25291590-20130317093523/@comment-26524765-20150623181433

http://elderscrolls.wikia.com/wiki/Racial_Phylogeny

Elves and Humans may mate.

It is less clear whether the  Argonians  and  Khajiit  are interfertile with both humans and elves. Though there have been many reports throughout the Eras of children from these unions, as well as stories of unions with daedra, there have been no well documented offspring.

Orcs and Humans may mate.

http://elderscrolls.wikia.com/wiki/Agronak_gro-Malog

Born from a mother orc and a father Imperial.