The difference between newborns, teens, and adults is negligible
compared to the single cell on the other side of the spectrum, which has
nothing that we commonly think of as a trait of personhood. The
commonality across the spectrum is that they all have eukaryotic cells
with Homo sapiens DNA. That’s it. That’s not something that
many of us get misty-eyed about. Very little sentimental poetry is
written about the kind of DNA in the cells of one’s beloved.
Very much worth reading, if you're interested in the abortion debate.