On the simple goblin: reproduction and life cycle

Goblins are born screaming and biting from the hide of their single parent after said parent has consumed enough raw material for their unique, disturbing biology to create an offshoot which grows and bursts from them like some kind of incredibly disgusting bubo.  A goblin is capable of surviving on its own within five to ten seconds from being born and their first instinct is to feed, usually upon their parent who, if they're smart, which is unlikely, has already buggered off. Newborn goblins are immediately accepted into goblin society, assuming they can be taught to not eat their elders immediately and how to swing a weapon. They continue on like this, eating and killing and occasionally splitting off a new goblin, until they reach maturity around age 4, at which point they become gendered, their otherwise smooth pelvises growing a spiked shaft for inserting their unborn young into a host. At this point they reproduce much like a xenomorph, infesting host bodies with an incubating egg-sack which will, when fully matured, burst forth in a gory display. These children are known as orcs, and we'll leave that for another post.