Sex differences in passion and play.
D000374:Aggression; D000818:Animals; D000831:Animals, Newborn; D005260:Female; D000882:Haplorhini / Q000502:physiology*; D006801:Humans; D008297:Male; D008425:Maternal Behavior; D010332:Paternal Behavior; D010988:Play and Playthings; D011187:Posture; D012726:Sexual Behavior, Animal