Sorry I'm late, LMM.
As Vince said, there was much debate about this question chez me. We settled on 12 months - by which time Louis was well able to support his head, helmet and all. We probably erred on the side of caution but, to paraphrase a diplomatic friend - why wouldn't you?
Louis is just over 20 months now, and is really getting into it. I think he was too young to quite appreciate it all at 12 months - not that he complained, I just don't think he got it. Now he points things out, inspects my back, sings and generally seems to enjoy it more.
And the 3 or 4 months that I had to wait to be sure that everyone was comfortable with him being on the back of a bike? I've got so many other memories from that time, that I don't recall any frustration at all.
