I think it is a little of both...like most things. Partly natural hardwired personality types and partly upbringing.
Some children have an easier time with some types of limits, and others have a difficult time with other limits.
Just like adults! The point in my estimation is that you don't dump the limits just because they are harder for some people to learn.
I always say that I was the perfect parent before I had kids, a decent parent when I had one child and didn't know a thing by the time the second came a long.
My two children are extremely different, and event the way I punish them has to be different. I do a LOT more praying now than I used to, which can only be a good thing.
I always say that I was the perfect parent before I had kids
This is sooo true. I was quite judgemental before I had kids. I think that is partly why I TRY to live by the standards I expected before I was a parent. Which is not easy, probably impossible. I find it interesting for my friends who have had kids 6-7 years after I did - there is a humbling that takes place in each of us parents. I try not to be so quick to judge. (But, the destructive thing really gets under my skin).