The joys of having a puppy! I have Flatcoated Retrievers, so know excactly how you feel! The retriever breeds love to involved with everything and everyone, and little people are better targets that big people. Children screaming and running around will encorage a young dog to jump and try and join in the fun. Try teaching the command 'Off'. I have 3 FC and they all know that 'Off' means put all your feet on the floor. This is used for jumping, climbing on sofas, checking out the work surfaces for things to steal, the list is endless. When he dog jumps up, ask the child to be as still as possible and lift the dog off, using the command 'off'. You can even use a treat when the command has been obeyed if necc. If you are persistant and consistant with the request, the dog with jump down with just the command. As he matures, he will proberbly grow out of it, but in the mean time he needs to know that it is not acceptable behaviour. I wish you the best of luck with your new bundle of... erm.. joy! It could be worse, you could have chosen a Flatcoat!!!!