Opposition to abortion and related issues is not limited just to conservatives and Catholics. For example, the site No Violence Period has a range of interesting articles from a left/libertarian perspective:
Highlights of this site:
The consequences of treating a fetus as a human being: Kevin Kelly‘s article in the Whole Earth Review. Kelly is Executive Editor of Wired.
The Indivisible Fight for Life: Civil libertarian Nat Hentoff describes how the right to life is inseperable from other issues such as poverty and the death penalty.
Jesse Jackson on Abortion: His 1977 article for National Right to Life News compares arguments for abortion to those for slavery.
Abortion: The Left has betrayed the sanctity of life: Mary Meehan criticizes the inconsistency in The Progressive.
The Abortion Papers: Bob Woodward unearths primary evidence that the Roe v. Wade justices knew they were drawing “arbitrary” lines and that the decision was “legislative.”