It always scares me when I hear of people who have lap children. My first question (that I always want to ask) is do you keep your child on your lap when you drive?
While flying the heavies (yes, I'm a pilot) you never know when you'll hit turbulence though sometimes you'll hear about it or see it in the clouds -- but you never know for sure. Or a quick deceleration on the runway could be like a low speed car crash. Are you sure you'll be able to hold and keep your baby safe in either one of these situations?
Just a few sense worth....