Abortion is unethical because of the right to life

The argument

The argument proceeds from a claim about what a fetus is to a claim about how it must be treated. The first step concerns biological identity. An embryo and fetus have all of the DNA of any human. On the view proponents take, that makes the question of species settled rather than open: the entity is not a potential human that becomes human at some later point, but a human organism from the outset, at an early stage of the development every human passes through. There is no moment in that development at which something non-human turns into something human, which is why proponents regard it as inarguable that what is present is a human life. The second step moves from that identity to moral standing. Human life is valuable, and the protection that value is given in law and in ordinary moral reasoning is the right to life, a right that attaches to human beings as such rather than to those who have reached a particular stage, acquired particular capacities, or been granted recognition by others. To make the right conditional on any of those would be to make it something other than a human right. If a fetus is a human being, it therefore has all of the rights of a human being, including the right to life. The conclusion follows directly. Aborting a fetus ends the life of an entity that holds a right to life, and ending a life protected by that right disrespects it. Since the fetus is a person in the relevant sense, proponents argue, abortion is unethical.

Premises

Counter-arguments

While a fetus or an embryo is biologically human, that is not a reason to give it the full rights of an adult human. An embryo is no more developed than many animals we kill to eat. Therefore, while a fetus may be human, it is not a person. Personhood requires a certain amount of development, and with that status comes rights. Since a fetus lacks the status of personhood, it does not have a right to life.

Rejecting the premises

[Rejecting P1] Carrying human DNA makes tissue human in the biological sense, a condition every cell in a body also meets, so the premise does not by itself pick out an individual with moral standing. "Inarguably" also states as settled the very question the debate concerns. [Rejecting P2] The premise slides between "human life is valuable" and "every human organism holds the full right to life", which is where the disagreement actually lies: the counter locates rights in personhood, and other positions in this question locate them in sentience or viability. It also omits the second half of the problem even for those who accept it — a right to life does not settle what may be required of another person's body to sustain it, which is what the sibling position turns on.