Child of a TARDIS

A Child of a TARDIS was an individual with the mark of the Time Vortex in their DNA.

If a TARDIS's emergency war protocols were enacted, only a Time Lord or a Child of a TARDIS could open a sealed TARDIS. (PROSE: River of Time)

River Song was the Child of the Doctor's TARDIS, having been conceived by Amy Pond and Rory Williams in the TARDIS while it was in flight in the Time Vortex. (TV: A Good Man Goes to War, Let's Kill Hitler, PROSE: River of Time)