this is incorrect, gender dysphoria has existed since mankind
and i quote
Among the sexual depictions in Neolithic and Bronze Age drawings and figurines from the Mediterranean are, as one author describes it, a "third sex" human figure having female breasts and male genitals or without distinguishing sex characteristics
Talalay, Lauren E. (2005). "The Gendered Sea: Iconography, Gender, and Mediterranean Prehistory". The Archaeology of Mediterranean Prehistory. Blackwell. pp. 130–148, especially p. 136. ISBN 978-0-631-23267-4.