Dr. Ray Blanchard on biological theories of homosexuality.

Dr. Blanchard is one of the heavy hitters in the world of sexual orientation research and theory. In this video, he briefly explains some of the biological correlates of sexual orientation, and goes into detail discussing his fraternal birth order theory.

Ray Blanchard is a researcher at the University of Toronto's School of Psychiatry. He is known for conducting studies that proved the more older brothers a boy has, the more likely he will be gay. Blanchard received his Ph.D. from the University of Illinois in 1973.