Argument: Christian leaders throughout history have been opposed to abortion
Tertullian, Apology 9:6, circa 220 - "For us [Christians] we may not destroy even the fetus in the womb, while as yet the human being derives blood from other parts of the body for its sustenance. To hinder a birth is merely a speedier man-killing; nor does it matter when you take away a life that is born, or destroy one that is coming to birth. That is a man which is going to be one: you have the fruit already in the seed."
Tertullian, De A ninta 26:4, circa 215 - "They [John and Jesus] were both alive while still in the womb. Elizabeth rejoiced as the infant leaped in her womb; Mary glorifies the Lord because Christ within inspired her. Each mother recognizes her child and is known by her child who is alive, being not merely souls but also spirits."