Don't be a smartass; it doesn't help the conversation.
1) No one is more familiar and in a better position to understand a child than their parents. Parents spend huge amounts of time dealing with their child and learning their quirks, emotions, and knowing their history.
2) Parents expend vast, enormous amounts of resources raising their children, and are directly and massively affected by the decisions that affect their children.
3) Without a doubt and by orders of magnitude, parents are most invested and concerned about their children's well being. There is simply no comparison to the love and care a parent feels towards their children. If there are people who can be trusted to do their best for a child, it's their parents.
4) Parents are legally obligated to provide the resources necessary for a child until they are 18, and to deal with the results of that child.
5) Parents MAY not always be the most rational decision makers concerning their children, and MAY not be the most expert on the decision at hand.
The obvious conclusion from this information is that PARENTS, by large orders of magnitude, are the ones who should be making decisions for their children. They are the defacto most trusted, invested, and authoritative people capable of making the decisions. In my opinion, the government should only step in when it is clear that the parents are giving worse general and long term care than the alternative (IE foster homes, etc.). That line is very, very low.