[proxy_user]

Here is what I was looking for:

"Early in the 13th century, Pope Innocent III stated that the soul enters the body of the fetus at the time of "quickening" - when the woman first feels movement of the fetus. After ensoulment, abortion was equated with murder; before that time, it was a less serious sin, because it terminated only potential human life, not human life.

"St. Thomas Aquinas (1225-1274) also considered only the abortion of an "animated" fetus as murder.

Is the official teaching of the Catholic church now different?

[Frank Sheed]

http://www.scriptureforlife.org/theme7.htm

[Nihil Obstat]

"Is the official teaching of the Catholic church now different?"

The Early Church Fathers and Abortion:

http://www.all.org/article.php?id=10118&search=ensoulment

[RobbyS]

The pope's ruling was based on the facts of biology as know at the time. Pro-choice doctrine seems still to be holding to 13th Century biology.