Answer: Dr Magnus Hirschfeld.
Explanation: Dr. Magnus Hirschfeld is a German physician and clinical sexologist, founded the first institute for sexology. Sexology is the study of human sexuality, including human behavior and functions. A vast body of research on human sexual development as well as the treatment of sexual concerns and dysfunctions was accumulated by the institute.Hirschfeld became interested in gay rights because many of his patient took their own lives.