Rec: Equivalence by introductory (Sherlock fandom)

I don't really post that many rec, and I don't usually post recs for a minor character in a fandom I'm only really on the edges of. But after reading this I though that that it really deserved a wider audience.

Equivalence by introductory
Sherlock (TV)
Teen And Up Audiences
Anthea(Anthony)/Mycroft Holmes
Summary: Sometimes you're Anthea, sometimes you're Anthony, but you're always still you.
Anthea is genderfluid, and very few people understand.

http://archiveofourown.org/works/206588