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 its mysterious disappearance they tried to convert Earth into one. This attempt failed, though many Adipose children were created. (DW: Partners in Crime)

The Wirrn had breeding colonies throughout 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. They also attempted to convert Earth into a breeding planet, through the use of ATMOS gas, but failed. (DW: The Poison Sky)