There might be a correlation, but it is almost impossible to prove that kids cause one to get better at one's job. For example, I am sure that people with kids

There might be a correlation, but it is almost impossible to prove that kids cause one to get better at one's job. For example, I am sure that people with kids (up to a certain number) earn more. But it might just be that they started earning more and then had kids. What I believe is that kids are a normal part of life very different from anything you have experienced before them. Having them has nothing to do with your career (or should have nothing to do with it), and they don't really care where you work up to a certain age.