Subject: There is a claim (spoilers for this & the season finale)...
Author:
Posted on: 2017-07-17 09:03:00 UTC
... in one of the Doctor Who Unbound audio books (they're AUs, and actually pretty awesome), that Time Lords will switch sex if they regenerate due to committing suicide. (The one I'm thinking of is Exile, the first full-length story to feature a female Doctor. She is probably an AU Three, having escaped from Time Lord justice presumably as Two.)
Well, so far that pretty much holds up. The two sex-change regenerations we've seen are the General standing in front of the Doctor's gun even when he's checking whether (s)he'll regenerate, and the Master literally stabbing him/herself in the back (assuming Simms did in fact regenerate directly into Missy).
Assuming this is part of the ongoing regeneration from the finale... well, he did trap himself on a deck full of Cybermen and walk in front of their guns while planning to blow the whole place to smithereens. It's not hard to call that suicide, too.
(Of course, if you do that, the Doctor practically always commits suicide...)
hS