The fraternal birth order affect postulates that gay men provide above average levels of child rearing assistance to siblings, thus increasing the survival of nephews and nieces and passing along genes that code for male same-sex orientation.

Question

Quizplus · Accepted Answer

The fraternal birth order effect refers to the finding that the more older brothers a man has, the greater the probability is that he will be gay. This effect is thought to be due to biological factors related to the mother's immune system response to male fetuses. It does not relate to gay men providing child-rearing assistance.

The Fraternal Birth Order Affect Postulates That Gay Men Provide