article does say women who have become men may join, but it appears to say that this only applies after surgery
Apparent interesting focus of female genitals & surgery as a requirement.
from Daily Mail:
In its new policy document, the policy also asks brethren to treat anyone going through gender reassignment with the ‘utmost compassion’ and support.
It reads: ‘It is important that any situation involving gender reassignment of a Freemason is treated with the utmost compassion and sensitivity and that the individual is supported throughout the process.
‘No candidate should be subjected to questions about their gender which could make them feel uncomfortable.’
But transmen would apparently have to answer questions (& provide the 'correct' answers) about their surgery. 
Some may of course be very happy to have this as a matter of public record. Some transmen (not very many though) have been very open and public in pushing forward trans rights and been at the heart of changes to law and policies.
Anyway, what do the Freemasons say about people who are non-binary? I have a feeling there could be some tension with Masonic traditions etc