The Doctor can only "turn human" with the aid of the Chameleon Arch. It has not been established whether it serves any other purpose, i.e. whether it can be used to change a human into a Gallifreyan or a Dalek.

Ad blocker interference detected!

Wikia is a free-to-use site that makes money from advertising. We have a modified experience for viewers using ad blockers

Wikia is not accessible if you’ve made further modifications. Remove the custom ad blocker rule(s) and the page will load as expected.