Radix
Karl M. Baer (20 May 1885 – 26 June 1956) was a German-Israeli author, social worker, reformer, suffragist and Zionist.
Born intersex and assigned female at birth, he came out as a trans man in 1904 at the age of 21. In December 1906, he became the first transgender person to undergo sex reassignment surgery, and he became one of the first transgender people to gain full legal recognition of his gender identity by having a male birth certificate issued in January 1907. However, some researchers have disputed his label as a trans man, theorizing that he was intersex, and not transgender.Baer wrote notes for sexologist Magnus Hirschfeld on his experiences growing up female while feeling inside that he was male. Together they developed these notes into the semi-fictional, semi-autobiographical Aus eines Mannes Mädchenjahren (Memoirs of a Man's Maiden Years) (1907) which was published under the pseudonym N.O. Body. The book "was immensely popular," being "adapted twice to film, in 1912 and 1919." Baer also gained the right to marry and did so in October 1907.
Despite him having undergone gender reaffirming surgery in 1906, exact records of the medical procedures he went through are unknown, as his medical records were burned in the 1930s Nazi book burning, that targeted Hirschfield studies specifically.