Githyanki Hatchery

The Hatchery is exactly what it’s name suggests, but it encompasses much more than that. Egg Mothers take care of Gith eggs until they are ready to hatch. Once hatched, the Egg Mothers accompany the newborn Gith to one of the nurseries in the founding civilizations.
  Most of these civilizations have their own nurseries, with the exception of Godsbreath. The destination of each Gith is predetermined by their parents. In the nurseries, the Gith are raised by individuals known as Guardians.
  This is where the Gith of the Citadel differ from their astral counterparts. Instead of being raised by Gith, those born in the Citadel are raised by the people of the founding civilizations, as part of the agreement made between the original Gith and the speakers.
  When Gith reach maturity, usually around the ages of 14 or 15, they return to the Citadel. The Egg Mothers are exclusively Gith, though not exclusively female.