Well depending on one's intelligence and specific experiences children can get very different and quite limited ideas about how the world works that may hinder them in the subsequent career especially if they start with menial jobs .Working full time prevents many people of developing a well rounded philosophy.I am not against someone putting his child to work just a bit to see 'how real life works' but forcing him to work full time for extended periods may fuck him up.By far the most successful people that i know are people coming from rich ,nurturing families where they never had to work.Most of these people have been able to keep their lifestyle and have some of the highest paying jobs while they are still 'playing' during work.