Abstract
INTRODUCTION: This article presents the history and rationales of conceptualization and classification of homosexuality and transgender identity in both ICD and DSM. We review the efforts that have been made (and those that remain pending) to improve psychiatric classifications with new scientific knowledge, changing social attitudes and human rights standards. METHOD: We conducted a literature search of the classification of homosexuality and transgender identity as mental disorders. RESULT: We provide a historical description of these concepts in ICD and DSM, including fundamental points of disagreement as well as arguments that have been effective in achieving changes in both classifications. CONCLUSIONS: Fundamental changes have been made in the International Classification of Diseases Eleventh Revision (ICD-11) in terms of the classification of sexual orientation and gender identity based on scientific evidence and the ICD's public health objectives. These changes might support the provision of accessible and high-quality healthcare services, and are responsive to the needs, experience and human rights of the populations involved.