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. (TV: Let's Kill Hitler, PROSE: River of Time)