The role of Magnus Hirschfeld and contemporary sexologists in establishing transvestitism (later transsexualism) is known, but the descriptions (and judgments) by WWI physicians (Herrn 2005, 97–98) are more obscure.
War physicians were concerned with the identification of transvestites as they were considered unfit to serve; like Hirschfeld the war physicians were aware of the feminine character of the transvestites. As they were concerned with preventing seduction, they included photographs to emphasize the femininity embodied by the transvestites. These were not typical of medical photography but perhaps resemble transition timelines in their argument.
We see the status of doctors as prescriptive anthropologists; though they were not helping the transvestites (unlike psychiatrists and surgeons) they documented life and offered opinions.