Why are males often more physically aggressive?

From secondary sources I’ve read that male and female humans are equally aggressive (how this is measured I do not know) but that males are more “physically aggressive“. But that a big part of the difference stems from male vs male aggression. For example, from what I can see from internet article statistics (not really statistics), females and males are similar in counts of “physical domestic aggression“. The term I keep coming across to describe humans (and other species) is “serial pair bonders“ or “