I believe the Yogyakarta Principles +10 also call for the removal of sex from the birth certificate.
It's interesting to see what other nations put on their certificates (the US puts 'race', which seems extraordinary to me). The govt. certainly need to know what sex we are for statistical purposes, but I do wonder if that would be the next step as we know TRAs, once given an inch will take many miles. I don't know where I stand on this, as my birth cert is useless to me, being in another name. I'm not even sure where it is.