Child labor is prevented by two types of laws. These two types are: laws that prevent children from working and laws that force them to go to school. Laws prohibiting child labor is what destroyed the apprenticeship system.
Laws prohibiting child labor also have made it so that children are a financial burden as opposed to a source of financial wealth.
People in western nations sometimes worry over low birth-rates in their nations. Well low birth-rates are a direct consequence of child labor laws. When children are a financial burden there is an incentive not to have them. When they are a source of wealth there is an incentive to have them.
The only people for whom having children is a source of wealth are people who are on welfare who are awarded more money the more children they have.
Compulsory schooling and prohibition of child labor have also resulted in extending adolescence.