The parents of Qa'a are unknown, but it is thought that either his predecessor Anedjib or Semerkhet was his father, since it was tradition to leave the throne to the eldest son.
Orang tua Qa'a tidak diketahui, namun diperkirakan bahwa pendahulunya Anedjib atau Semerkhet adalah ayahandanya, karena tradisi tersebut meninggalkan takhta kepada putra sulung.