Why do some men behave badly?

I feel like my kids go against alot of this. My oldest son has always been a quiet well behaved kid. He never liked getting in trouble as a kid so he didn't. His teachers loved him and we routinely got the "your son is so well behaved" remarks. End result....he was bullied mercilessly all through school. As a parent that's a helpless feeling watching your well meaning son suffer through school. He's 21 now and he made it through it but still has scars from those years and he's very guarded with people.

My daughter is a very dominant personality. She's the first to step forward in most situations and doesn't take lip from anyone quietly. She also has zero problems speaking up for others. She's 18 now and is currently going through a battle with her roommates at the dorm. As parents we never need to step in for her ....she will handle it 😂.

I'm sure as parents we're the reason they're like this as we're ultimately responsible for how they acted as children but at the same time I feel like they were just built like that.