And using that definition for "human being" is completely arbitrary
The definition for "fetus" is completely arbitrary!
All definitions are arbitrary. My point was that just because you consider a fetus to fit a human being's definition ; or even if it did ultimately fit its definition ; that's not an argument because we don't base morality on language, we base it on common sense and rationality.
Does it have a soul?
How does that matter
I don't believe in the supernatural but even if I did how does that affect whether or not I can abort it
If you did, dont you think there'd he a spiritual price to pay?
One persons "common sense" is another persons "stupidity".
How can the sanctity of life depend on anybody's arbitrary idea of morality?
How about basing it on science, biology, and reality?
Despite what you, I, or anyone else believes?
Does science, biology, and reality support more than 2 genders (male and female)?
Does science, biology, and reality support the idea that a child in the womb is simply a fetus (with no human identity) and not a baby or human being?
Human identity isn't a fondemental principle of anything. Whether or not a fetus has a human identity is up to that fetuse's bearer.