Stephan Kinsella makes an exhaustively comprehensive case for self-ownership, which is the fundamental prerequisite of all human freedom.

I recommend reading Kinsella's piece in its entirety, but below I summarize what I found to be his key arguments.

Kinsella first describes ownership as coming from the principle of "first use". First use is the idea that unowned scarce resources come to be owned when they are first used. First use is easily applied to unowned land and other such scarce resources. But what about living beings? Though the concept of first use is useful, how does it explain initial ownership? Does a human being de facto own his own body at conception? Birth? Is ownership merely arbitrary? Kinsella points out:

But for bodies, things are not the same. As noted above, one is not really the "first user" of one's body in the same sense as one is the first user of a previously unowned thing that one appropriates. It's not as if the body was just lying, unoccupied and unused, in the wild, waiting for an occupant to homestead it. And moreover, as noted above, the occupant is not exactly the first user of his body, with respect to his parents.

Additionally, to homestead an unowned resource presupposes one already has a body, which one uses to act in the world and to homestead unowned things. But this is not the case for "homesteading" one's body. One has no body before one gains rights to it.

Why do I have a right to my own body that is superior to any other individual's right? What is the source of this right?

So, who owns a child's body? Initially, the parents own it as a sort of temporary trustee. The parents, as the producers of the child, have an objective link to the child's body that defeats any claims of outsiders (unless the parents sever this link by abusing their position). That is, parents have a better claim to the child than any outsiders, because of their natural link to the child. However, when the child "homesteads" or "appropriates" his own body by establishing the requisite objective link sufficient to establish self-ownership, the child becomes an adult, so to speak, and now has a better claim to his body than his parents.

Self-ownership is spawned from the act of appropriating one's body: acting, which implies will, to sustain one's existence establishs self-ownership. To the extent that one cannot act, it would follow that one cannot own.

Action, which is inseparable from will, is the fundamental precursor to ownership. Once an individual has acted to secure self-ownership, no one can make a superior claim of ownership over said individual without such individuals willful, non-coerced consent. This is why criminals, gangs, and governments are inherently abject bodies: they usurp the established property right to self-own.

And when they do (and will), we have a right to fight back.