Quote:The novels all dealt with this. It was The Doctor playing a trick on the Master. He was never half-human
The novels aren't canon.
Besides which, The Timeless Children has thrown everything up in the air. People are assuming that the child is a completely alien being, but for all we know perpetual regeneration is discovered on Earth in the far future, on on some alien world that human colonists have reached.
Chibs might even be going (God help us) for some kind of time paradox nonsense. Something like: The Doctor IS a Gallifreyan or Gallifreyan/Human hybrid born in the far future, the first such born with natural perpetual regenerative abilities, but was sent back through time so that Gallifrey could have regeneration in the past.
Wasn;t there a rummour that his real and secret name was to had been said to be God?