Dr. Crosby has been a research psychologist for the past 15 years at the University of California, San Francisco-Center for AIDS Prevention Studies (UCSF-CAPS). Much of his work has been researching the behavioral aspects of HIV transmission among gay men. He received his Bachelors degree in Psychology in 1987 from the State University of New York at Purchase and a Masters degree from Columbia University, Teachers College in Developmental Psychology, in 1988. He started his Doctoral studies in Clinical Psychology at the Wrght Institute, Berkeley, California in 1988 and in 1990 began working as a research assistant at UCSF-CAPS. He interned at the Queens Medical Center in Honolulu, Hawaii in 1993-4 and was awarded the PhD in 1994.

Returning to San Francisco as a post-doctoral fellow at UCSF-CAPS he completed a Masters in Public Health at the University of California, Berkeley in 1995 with an emphasis on Epidemiologist and Biostatistics. His research to a unique and important innovative HIV prevention programs to the men and women they serve. His work extends to Europe, South Africa and Australia in both HIV prevention and substance abuse among gay/bisexual men. Dr. Crosby has authored and published numerous peer reviewed journal articles and has presented his findings at numerous national and international Aids Conferences in his 15-year tenure at UCSF.