https://sciendo.com/article/10.2478/sh-2020-0012

A Rational Theory of the Rights of Children by Ian Hersum is an interesting entry.

In my mind, there should be a distinction of concepts:

The Child as a Latent Self-Owner:

• They are a Self-Owner as a Human Being (HPC), and have the inherent potential to become a Legal and Moral Agent.
• Their ownership is Latent, because their capacity for decision making is still in development, and is demonstrably insufficient for Self-Guardianship.
• Guardianship, the positive of maintaining the rights of another Human that is incapable of doing so themselves.

With these givens, this follows:

• Children are not owned, they cannot be "bought and sold" without aggression.

• Children have Guardians, the position of a Guardian is distinct

• Guardianship itself can be traded or established via homesteading.

• Natural Parents are the default Guardians, but must gradually give up the extent of their control until the Child becomes an adult.

• Guardianship should be considered similar to maintaining a Trust in a voluntary fashion. Any type of abuse of this trust can be evaluated similarly to any other form of aggressive violence.

• Child abusers can be contested directly, or via arbitration if available, similarly to how anyone witnessing a crime can choose to step in and offer help to the victim.

Examples:

• Parents may decide to abandon a Child with someone capable of keeping them alive and protecting their rights. This is normally called an Orphanage and Adoption.
• A person that finds an abandoned Child can work to provide and raise that child, this effort in itself providing them the justification to being considered the Guardian.
• The more civilized and formal the location, the more notification is required for any Guardianship status changes, to avoid forestalling.
• You can step in to stop aggression, and your actions can be evaluated for legality by observers and participants. The base assumption when rescuing a temporarily incapacitated individual is that they would want to be saved and taken care of until the time where their ability to make decisions is restored.

Reference: HPC - Homeostatic Property Cluster https://plato.stanford.edu/entries/species/#SpecHomePropClusKind Simple example: "Something that looks like a Duck, quacks like a Duck, and has the DNA of a duck, is most likely a Duck - even if it's missing a wing." When defining Humans in this manner, the temporary inability to make decisions does not deprive anyone of their inherent right as a latent self-owner or their potential for Legal and Moral Agency.