[feisty]

Good question!
The law here in my state used to be when their legs can reach the foot pegs. It changed last year to 8 years old.

My daughter is now 11 and has been on the back since she was 7. The last couple of years she has been doing about 140 km of commuting a week with me no matter what the weather. She doesn't mind the rain but hates the really hot days (as i do too) because all the gear still has to be worn. I put a rack on the back to boost her and my confidence. She has more bike gear than I do. Most of it is better than mine too. BMW jacket, hein gericke leather pants and boots. BMW helmet. I have had to scour the world for this gear because you cannot get kids road bike gear here at all. Most of it has come from Germany via eBay. It seems that kids on bikes must be more accepted there as there is a lot of great gear in small sizes available.
I see it as a great lesson on risk management for her. As for me, well it takes defensive riding to a whole new level when you have your only child on the back.

I cop a bit of grief from her mum over it.....