I first became a vegetarian when I was nine in response to an argument made by a radical babysitter. My great change - which lasted a couple of weeks - was based on the very simple instinct that it's wrong to kill animals for food.
Don't force your kids into sports. I never was. To this day my dad has never asked me to go play golf. I ask him. It's the child's desire to play that matters not the parent's desire to have the child play. Fun. Keep it fun.