Of course it is part of a mothers body, it cannot exist outside the mother. I disagree. Until an embyro becomes a fetus, it should not have rights of citizenship that somehow make it OK for your morals to override a mothers own wishes. Then you agree with Roe versus Wade which holds that a fetus has rights, I don't argue with this. I argue against your contention that a first trimester embryo, even a single fertilized egg cell, is due rights of citizenship.
Then why does it have DNA different than every other part of her body? That does not make sense. What are you trying to say? Let me clarify a single cell is every bit as important as any multi-cell version. The number of cells an organism possesses is not what defines whether it is a person or not.