Final answer:
The removal of homosexuality from the DSM was influenced by scientific evidence, advocacy and activism, and social and cultural changes.
Step-by-step explanation:
The removal of homosexuality from the DSM as a psychological disorder was influenced by scientific evidence, advocacy and activism, and social and cultural changes. Scientific research showed no evidence to support the classification of homosexuality as a mental illness. Advocacy and activism by individuals and groups, such as Frank Kameny and radical activists, played a significant role in challenging and changing the perspective of mental health professionals. Additionally, social and cultural changes in society led to a shift in attitudes towards homosexuality, recognizing it as a normal and natural variation of human sexuality.