After their failure, the homeworld gems had no chance against the Crystal gems, all their soldiers were turned into baby gems, they didn't know how to deal with this creatures, after their surrender, the diamonds asked for help to the earth, all the babies were send to couples unable to have their own children.
It was the end of the war between gems and humans, for his services and sacrifice, Greg universe was proclamed king of everything forever.
The end.

“Apparently, we’ve been going at it all wrong making our fighters tough and durable. What we really need is soft and fleshy. Like… humans. We need more gems that are like humans. Now, the only question is, how can we make human-gem hybrids?"