Genetics and environmental influences seemed logical. Implications for the Kin Selection Hypothesis". Retrieved 19 August Published August 14, They also found that "unusually high" proportions of homosexual males and homosexual females were Rh negative in comparison to heterosexuals.
In many women, particularly, sexual attraction tends to follow on the heels of strong emotional attachments with partners of either sex, Schwartz said.
However, this difference was not hypothesized a priori, was not large, and was the only group difference found out of many tested. Biology Birth order Demographics Environment Heterosexual—homosexual continuum Homosexuality and psychology Kinsey scale Klein Grid Neuroscience Prenatal hormones Sexual inversion Sexual orientation change efforts Conversion therapy Sexual orientation identity Timeline of sexual orientation and medicine. In interviews to the press, researchers have pointed that the evidence of genetic influences should not be equated with genetic determinism. Re-examination of the maternal immune hypothesis".
The second group comprised 16 men whose sexual orientation was unknown, but whom the researchers presumed to be heterosexual.