From a 2014 Imamother thread:
"My friend Max is F-M [that is, female to male transgender], and for years has wanted to convert to Judaism. He was told that he cannot because of his surgeries. He is absolutely heartbroken about this, but is trying to accept that Hashem wants him to be a Noachide in this lifetime."
Why would a female having had such surgery disqualify her from conversion?