Richard Colestock Pillard (born 11 October 1933) is a professor of psychiatry at the Boston University School of Medicine.
His youngest daughter, Elizabeth Jane (Eliza) Pillard, is a social worker specializing in child psychiatric issues in Vermont.
This family history seems to invite a biological explanation, and it made Pillard start thinking about the origins of sexual orientation.
In all studies they found rates of concordance variantly consistent with the hypothesis that homosexuality has a significant genetic component.
The Council for Responsible Genetics and other researchers have criticized this work for using a self-selected sample, a problem which later studies have attempted to remedy.