Our reflections on the nature of being human teaches three critical lessons. One, the right to life, liberty and the pursuit of happiness is for humans as humans. That's why they're called human rights, not person rights.
Two, equality has nothing to do with some physical trait that all humans share. No one is less deserving of respect or value because she has decreased capacities or has missing, altered, or underdeveloped body parts.
All humans beings have something by virtue of their humanity that gives them equal and unalienable rights, but this valuable thing is not physical. What is it? It is their non-physical self. Most people call this personhood, others have called it a soul. Whatever you call it, it's what really matters.
Being human with unalienable rights is bound up together with being a person. One can't be separated from the other. All human beings, at any stage of existence, are valuable persons.
Stand firm in Christ,
Koukl, Greg. Precious Unborn Human Persons. Pages 31-32.