This is just my thinking, but I have always imagined that when we are born, God gives us an appointment with death, in this case, He likely pointed at both of them and issued the same appointment.
Of course when we murder someone, or abort them, it is a grievous sin, because it actually disrupts the plan of God for that person, which might be why murder cries out to God for vengeance.
Just my opinion, certainly not an article of faith.