The Rev wrote:
"Thus the needs of the woman should supercede the needs of the fetus, since the fetus is only better than a steak in its potential."
Peter asked:
"But why should the needs of the women supercede the needs of the fetus?"
The woman's needs supercede the needs of her fetus because, according to a rational theory of individual rights (cf. "The Rights of Man" in The Virtue of Selfishness by Ayn Rand), individual rights apply to actual human beings (which the woman is), not to merely potential human beings (which the fetus at best is).
On a proper theory of individual rights (i.e., on a view of individual rights which is based on an objective view of reality and a rational view of epistemology and morality), the woman has sole discretion over the choice of whether or not to carry her pregnancy to term. Some argument may be made for later stages of pregnancy, but there is no question that during the first trimester of pregnancy, a woman has the sole right of choice in this matter. She may choose to keep or abort her pregnancy for any reason she chooses.
Thus, when Peter points out that "Abortions are performed even if it is just the whim of the mother--or even in many cases when she is pressured into it by family and friends (in the case of a teen pregnancy, for example)," as sad as this might be to some people, it is the case that the mother still retains the right of choice, regardless of how she arrives at the choice. 
Many people do not like to see others act freely on their choices, and thus seek to stifle them in some way. If they are not successful through legal procedures, some even attempt to use force against those doctors who do carry out abortions. Just another example of how abandoning reason leads to the use of force.