I agree with what has been said, it is a decision that you need to make as a parent based on the childs level of understanding and the ability to follow rules while being a passenger. That said...I am a parent of two little girls, my soon to be 3 year old bugs me constantly to take her for rides on the bike and I won't let her. I told her that when she gets a year or two older I will get her a mini dirt bike of her own and that when she can ride that then she can go with me. Also, she is tall and smart for her age...as in she knows how to start my bike from watching me do it and knows where the horn and throttle are and how they work...I have a feeling I will have a hard time keeping her off of bikes when she gets older. She has it in her blood I think...I ride, her grandpa rides, and her great grandpa rides. My first time on the back of a bike was when I was 5 btw, and I remember being real scared at first so take it easy if and when you take your little guy out.