My own opinion. While it has been suggested a Time Lord can change gender with a regeneration, we haven't seen that much. The Doctor has been male through all 11 of his incarnations. The Master has been male in all of his regenerations (although a few of those have involved stolen bodies.) For the Time Ladies, they've maintained their gender as well. (Although the only two we've seen are Romana and River Song.)
dont forget Susan and Chancellor Flavia and the Rani....
Did any of them actually regenerate? I was referring specifically to Gallifreyans who have regenerated, either on or off screen.
As far as I know, only Kate Omara ever played The Rani. Only Carol Ann Ford ever played Susan (and it was never actually verified she was Galifreyan.) Only Dinah Sheridan ever played Flavia (Okay, I had to look that one up.)
The other Time lord who regenerated numerous times was Cardinal/Chancellor/President Borusa, who was played by a different actor every time he showed up.
The only reference Canonically to a gender changing Time Lord was one called The Corsair, mentioned in The Doctor's Wife, who the doctor referred to as being "a bad girl" when she was female.