Its all the years of stress and worry they give us grandparents when they are young, and when they hit their teenage years, their parents can take it on, me and the mrs panic now when one of ours has had a fall of a bike, or when they start coughing or get a bit of a temperature, I think its a grand parent thing as I dont remember worrying as much when my kids were at a young age, thats what they tell me anyway, but I suppose thats because our own parents were there to do it for us, make sure he enjoys his birthday rs, gives you a good excuse to spoil him a bit more today.