four presuppositions
Let’s take a look at these four ideas.

1-  Just as some believe the first living cells came into existence out of primordial soup by “accident” billions of years ago, an individual human life can come by accident. Unlike a planned pregnancy, an unplanned pregnancy disrupts people’s lives, and a woman might need to correct the mistake.

2-  Whereas some people believe in “the sanctity of human life” pro-choicers believe in a concept called the “quality of life.” This means that a human being can gain and lose value according to its condition and surroundings. A baby might be born into poverty in which living doesn’t feel much like living. The quality of life, of course, refers to how well someone lives. Some people live happy lives, and some living conditions make death more appealing.

3-  Pro-choicers believe that human beings determine value. Nature created human life, but nature does not give us value.  Because we comprehend our own existence we determine the value of it. Life has value in our eyes. 
     Margaret Sanger, the founder of Planned Parenthood, taught that human beings get their worth from each other.  She said, “The first right of every child is to be wanted, to be desired, to be planned with an intensity of love that gives it its title to being.” A child gets its value from the love of other human beings.
     This concept is important to the pro-choice position.  A woman must decide whether or not a fetus inside her holds value. The fetus cannot determine its own value.

4-  Pro-choicers hold a different concept of morality than pro-lifers do. They believe that a woman must decide whether abortion is right for her. 
     Pro-choicers either do not believe in moral absolutes, or they do not believe that absolutes can be known. Perhaps they exist, but we could never prove them, so we might as well decide for ourselves what is right.
The pro-choice position appears more open.  Pro-choicers give a pregnant woman three options:  keep the baby, put it up for adoption, or get an abortion. Pro-lifers only offer the first two. Pro-choicers see in shades of gray while pro-lifers see in black and white. Pro-lifers say, “No!” to abortion. Pro-choicers say, “Maybe.”
     Does this mean that pro-choicers are more open-minded?  Not necessarily. Open-mindedness pertains to one’s willingness to understand, not one’s willingness to agree. Being open-minded does not require me to agree with your conclusion. Opening my mind helps me to understand your point of view, not necessarily to agree with it.