First of all we should define the “ parens patriae” term. Basically, it is the principle that political authority carries with it the responsibility for citizen’s protection. So, it is any authority that is regarded as the legal protector of citizens unable to protect themselves.
The principle of liberal individualism has helped in expanding of children’s distinct personhood and, in doing so, has helped shape the concept of parens patriae. It has been the impetus behind, and provides justification for, the extension of notions of full personhood to children as a class.
The past few decades have thus seen development in the area of children’s individual rights, but children’s rights have in many respects continued to be viewed as secondary to parents’ rights. Critics of the parental rights doctrine have argued that it conflicts with liberal ideals because the creation or expansion of parental rights necessarily restricts the rights of children.
They argue that a strong conception of parental rights subjugates children to the choices of another, subsumes their interests within those of their parents, and fails to recognize that children and parents interests can all too – easily diverge. Parents’ rights include their ability to make choices for their children (religion, education, etc.) that can sharply limit their future abilities to choose their own life course. The state will often use the doctrine of parens patriae to intervene in even the intact family, in order to protect the individual rights of children.
Historically, the state exercised the parens patriae power when no guardian was available to a child. That power has gradually expanded.
In the nineteenth century, state legislatures began enacting child abuse and neglect laws that authorized governmental intervention into abusive parent-child relationships. And today, laws give states even broader powers to protect children.
States assert jurisdiction in the name of children’s best interests in actions before separate juvenile courts, as well as in custody and adoption actions (including, perhaps most notoriously, allegations of child abuse and neglect).
The state’s interfering when necessary to safeguard the liberty of children from harmful incursion by others (i.e., parents or guardians), is arguably the very embodiment of the John Locke’s ideals of government. You could try here to get more information.