I waited till ds was 6 m. I wouldn't even let him have water before then. But he was a real fast learner when it came to eating food. Dh had to argue with MIL because ds would be contintedly eating whatever was on my plate, MIL would try to stop him saying he's too young, he doesn't know how to eat. Dh would say,"mother, he's eating. Let him eat.". It took a few tries before she quit worrying. We mostly eat very healthy unsalted or lightly seasoned home cooking. As soon as I saw the chocking and gagging wasn't a problem I just let him eat whatever he wanted. But the babyfood jars came in handy whenever we went out shopping or something.
But to answer your quiestion- it might be a myth but I went with the prevailing theory that they get different stomach bacteria or something when they turn 6 months- strictly bf'ing. I weaned ds at 23 m.
