The difference is quite simple, a child under the care of his parents is not a slave, or at least he is not supposed to be. A slave is a human being forced into involuntary and total servitude for the entirety of his life. A child is only under the authority of his parents until he turns 18. As of 18 years of age he/she is considered an adult and can do as he/she pleases with his own life. It needs to be remarked that authority is not the same as forced involuntary servitude (though some kids might be inclined to use such term when asked to collaborate with reasonable house chores but that is just plain hyperbolic immaturity). The emancipation of an actual slave by a slave owner is seldom voluntary and most times it is forced (it took a Civil War to settle the question). The emancipation of a kid takes place for very different reasons:
-The parents are found to neglect the well-being of the child (exploitation, sexual abuse, violent physical or psychological abuse, etc). The child is then emancipated, that is to say removed from his parent’s care and either becomes a ward of the State or the adopted son or daughter of another family).
-The child has left school at age 16 and starts working and earning his/her own salary and achieves financial independence from his /her parents. He/she marries or enters the army.
It is evident that the only similarity between the emancipation of a child and the emancipation of a slave is the use of the same word that has the same etymological source but very different meanings.
Between the times of actual slavery and now. Things have changed quite a bit. There was no legal framework for the emancipation of children, let alone laws preventing their neglect by parents. Emancipation of slaves occurred a long time before the emancipation of children was established in the 20th century. It did take place de facto before that but there was no legal framework.
