A bully asserting their dominance on the playground or in the high school halls is likely to have more children in adulthood than their peers, new Brock University research has shown.
I didn't change the title, but without access to the original article, it seems like a correlation not causation.
My guesses are that there ate multiple factors at play:
less educated people make more kids
"nice guys finish last" - assertive and more socially active people are more likely to find a partner and make children
forcing others to follow perceived social dynamics means internal pressure to follow them oneself; having children is a social norm and expectation that is expected to be followed
I'd try and look for papers to see if my guesses hold any water, but time eludes me.
Have you not had your morning coffee yet? 😄 The study purports that bullies have more kids, not that people with more kids were/are bullies. It investigated the relation in one single direction, not both.
I think being assertive and more socially active meaning you're more likely to be a bully is a bit of a myth. Although the cliché school or work bully may be assertive and socially active, there are many unpopular and awkward people who bully those around them, and it just goes unnoticed.