+1. I don't know about cancer, but having kids just makes you more productive for a given amount of time. Not necessarily at a coding level, but at the meta/self-management level where you decide what really needs to be done.

It's probably aligned with the "ask the busiest person you know" type of thing.

And yes I am more passionate about coding now, but that came from boredom. I learned Ruby then Haskell because I was bored of churning out C# all day, and I am glad I did. This lead me on to Elm which is my side project engine.