They do not have access to positions of power and authority at all, although some adult might choose to use his or her access in behalf of the child. Children cannot sue in court, bring charges against those who harm them, or otherwise force the various social institutions to act in their behalf. They have no vote. They cannot enter into contracts for their own benefit. And what they cannot do makes children incredibly vulnerable to abuse and exploitation.
Children are literally powerless on their own.
In our society, as in most societies, the social institutions are designed in such a way that adults are expected to provide for the needs of the children. Look at what has been happening on a national scale. For about 20 years, the nation has been cutting taxes for wealthy adults while borrowing huge amounts of money to finance government programs that for the most part benefit adults. Spending on schools that would directly benefit children has declined as a percentage of the federal budget. While spending on child welfare has increased, the money goes to adults, and it is unclear just how much of the money spent actually benefits the children who are the intended beneficiaries.