On This Day....

... in 1990 the World Health Organisation passed a resolution to remove Homosexuality from it's list of mental illnesses.

The World Health Organization's ICD-9 (1977) listed homosexuality as a mental illness, and in 1990, a resolution was adopted to remove it in the ICD-10 (1993).

Wikipedia

The ICD-10 then carried the note-

Sexual orientation by itself is not to be regarded as a disorder.