I have a 2.5 year old daughter, and I've found that once we got past the sleepless nights phase, I became more productive on my side projects than I was before she was born.

I have dramatically less free time to work on them, but out of necessity I've become much more focused and disciplined about how I use it (no more tv, aimless web surfing, etc.). The net effect is that I'm getting a lot more done. Meanwhile, my single friends are complaining that they don't have any free time for side projects. Hah.