Theo Sandfort is a Professor of Clinical Sociomedical Sciences (in Psychiatry) at Columbia University and a Research Scientist at New York State Psychiatric Institute. He has a longstanding career in social science research on topics such as HIV and sexual risk, sexual orientation and mental health, and gender nonconformity. He has a particular interest in male same-sex sexuality and HIV in Africa. He published widely in high impact journals and has (co)edited several books including Sexual Behaviour and HIV/AIDS in Europe and The Dutch Response to HIV: Pragmatism and Consensus, (1998), and Lesbian & Gay Studies: An Introductory, Interdisciplinary Approach (2000). He serves on the editorial board of major journals including Archives of Sexual Behavior, Journal of Sex Research, and Culture, Health and Sexuality.