An excellent article regarding a woman's recent journey from a pro-choice atheist to a pro-life Catholic is here. It helped me to understand both sides of the issue better and reinforce my own (thanks to Amy for the article).
"For You Formed my inward parts; You covered me in my mother's womb. I will praise You for I am fearfully and wonderfully made; marvelous are your works, and that my soul knows very well. My frame was not hidden from You, When I was made in secret, and skillfully wrought in the lowest parts of the earth. Your eyes saw my substance, being yet unformed. And in Your book they all were written, the days fashioned for me when as yet there were none of them." Psalm 139:13-16