A parent of Jed Whedon was a screenwriter.
Although not constituting completely reliable evidence, several congenital traits such as attached earlobes, a widow's peak, or the cleft chin, may serve as tentative indicators of (non-) parenthood as they are readily observable and inherited via autosomal-dominant genes
=== Empathy ===David Haig has argued that human fetal genes would be selected to draw more resources from the mother than it would be optimal for the mother to give, a hypothesis that has received empirical support

