Jesse
As mentioned by @s18009 in earlier post, medical intervention has been defined and based on that even GD certificate should suffice to apply for binary gender marker.
Also, the understanding is that we dont have to get govt documents updated to TG marker if we want binary gender markers on legal/govt documents.
s18009
In a webinar by Humsufar trust, lawyer Trupti Tandon noted that based on the language of the Transgender act it appears that we need to first apply for Transgender certificate and then apply for binary gender marker. She also noted that based on language of rules, however, it appears that we can apply for binary gender markers directly (by providing concerned medical document) without having to apply for TG certificate.
So it will be better, If someone has applied or has info about applying for binary gender marker through the portal, updates us here.