Well to be honest; one thing does happen when you have kids... you start to like them. This changes you dynamically. Sometimes it enhances your other interests, sometimes it distracts you. But one thing for sure is, you will have as much passion for them as you do for any of your hobbies. For a man, it takes more time, but one day you'll be in the garage and the urge to play with your son is as strong as the urge to finish whatever thing you're working on. Hopefully they grow up liking what you like.