What is a female doctor called?

A doctor. "Doctresse" is an archaic term denoting a female doctor, but just like "professoress" and "instructress" are old terms which have been abandoned as there is no need for them, doctress is no longer used. According to the Oxford English Dictionary, 'doctress' cites it as 'rare,' and specifies that a note for its use: "Now only used when sex is emphasized; in which case also woman-doctor, lady-doctor, are more common."