Physical or relational/psychological aggression person has to mean it, harm is intended. Are there gender differences in aggression? what are they like, how do we explain them. Gender differences in both physical and interpersonal aggression. Women are better at emotional aggression rumours, gossip, slander. Why would males be more physically aggressive than females. Reproductive biology males have mobile sperm and they want it as many places as possible. Females get pregnant and it is much more costly. Males want as many possible offspring as possible, motivated to win as many possible females. Men want to display that they have good genes biggest and strongest male will win against other males. Males kill other males way more often than women kill women. Men are 40x more likely to kill unrelated other males than women are to kill unrelated other females. Also more likely to be arrested for aggressive crimes. Women are more relationally aggressive mean to one another on purpose.