Research shows that a chemical called HEX that babies give off from their heads calm men but make women more aggressive.
This could be a chemical defence system we inherited from our animal ancestors, making women more likely to defend their babies and men less likely to kill them. Odors affect behaviour in the animal world in plenty of ways. For example, a rabbit mom will attack her pups if they smell like another female rabbit.
We humans like to think we are above all that, but scientists are increasingly finding that odors affect us more than we think!!