Comment by freehorse

I suspect a lot depends on the age and motor development level that people here are not talking about, and that there should a certain age where a kid has not developed the muscles as much as to bike fast enough to pedal comfortably and fast enough to be able to balance, and an age after where, once one has figured how to pedal comfortably, balancing would not be that hard. I would assume that it would be harder to balance in the first place if you have to struggle putting force to pedal, which also probably means you cannot develop a sufficient speed either.