Breeding

Most species are capable of having sex, but only some are capable of producing offspring, most notoriously Humans and Orc/Elves. The resulting offspring can be either of the parent species or a half breed species. It works like this; If an Elf and a Human breed, there is a 25% chance that the child will be Elf, 25% chance to be Human, and 50% chance of being a Half-Elf. If a Half-Elf breeds with a human, there is a 75% chance the child will be Human and 25% chance of being Half-Elf. A Half-Orc breeding with a Half-Elf can produce a human 50% of the time and either a Half-Orc or Half-Elf 25% of the time (split evenly, 12.5% of the time each). 
A Goblin breeding with a Gnome can produce a Kobold.
Category:World lore