From Stand To Reason:
“[A]t all stages of our lives — from the embryonic through the fetal, infant, child, and adolescent stages and into adulthood — we are human beings with dignity and the right to life. Our dignity does not come from having achieved a certain level of intellectual proficiency or even conscious awareness. … We have our dignity in virtue of the kind of entity we are: that is human being, a creature with a rational nature. And we became that when we came to be.”
~Dr. Robert George
Added by American Texan:
At no time is the human being a blob of protoplasm. As far as your nature is concerned, I see no difference between the early person that you were at conception and the late person which you are now. You were, and are, a human being.
~Dr. Jerome Lejeune