Breeding planet

A Breeding planet was a planet utilised by a spacefaring species for the sole function of procreation.

The Adipose maintained breeding planets, as their young were created parasitically by injecting seed into animals. Adipose 3 was such a planet, and after it's mysterious disappearance they tried to convert Earth into one. this attempt failed. (DW: Partners in Crime)

The Wirrn had Breeding colonies troughout the Andromeda Galaxy, until they were destroyed by Human colonists. (DW: The Ark in Space)

The Sontarans maintained breeding planets to clone millions of their kind. (DW: The Poison Sky)