If you oppose abortion because you think it's against God's will, I respect that and you should live by that. I do not think that it is against God's will and therefore you should respect my approval of abortion. You should not impose your religious belief on me. They had a point. The pro-life response accordingly, was very direct.
Religious belief is a powerful motivator for the individual person.
But this is not merely a religious issue, it is primarily a human rights issue, a civil rights issue, and our nation and other western nations, make laws to protect civil and human rights. The second major goal of teaching was equally related to the teaching of fetal development. A typical lecturer in the first 20 years of this movement would spend about half of his or her time giving a scientifically accurate presentation proving that human life began at fertilization. Typically this was by slides, sometimes by a movie and more recently by video. If effective, those in the audience would be convinced that this was human life and from the beginning.