Historically, what measures have been used as a basis for estimating the prevalence of gender dysphoria? (Select all that apply.)

A) Polls conducted by telephone
B) Use of the diagnostic codes for gender identity disorder and gender dysphoria
C) Surveys conducted on admission and discharge from hospitals
D) Rates of gender-affirming surgery
E) Applications for legal gender change

Historically, the prevalence of gender dysphoria has been estimated through various indirect measures due to the lack of direct large-scale surveys specifically asking about gender dysphoria. These measures include the use of diagnostic codes for gender identity disorder and gender dysphoria in medical records, rates of gender-affirming surgeries as an indicator of individuals seeking medical transition, and applications for legal gender changes, which reflect those seeking to align their legal identity with their gender identity. These methods, while not perfect, provide insights into the prevalence and trends of gender dysphoria in different populations.