There is one underlying issue surrounding the abortion debate. Here is the question: Is a zygote (or embryo or fetus) a living human being worthy of the same inalienable rights as those who have been born? If you say no, then you probably don't have a problem supporting a woman's right to an abortion. If you say yes, then you are entitled to not have an abortion. What you are not entitled to is to force your belief on women who are not you.
There are reasonable and intelligent people on both sides of the issue. I can respect your right to believe that life begins at conception. What I expect in return is a reciprocal respect for those who do not share your conservative beliefs.
There is a huge difference between the two beliefs on when human life begins other than a disagreement over that moment. The difference is that most conservatives who strongly believe life begins at conception want to force other women to bow to their moral compunction about abortion and they want their beliefs on the issue to be compelled by law. But those who believe a fetus has no rights are not forcing the Right-to-Lifers to get abortions. If those who do not support abortion feel bad that so many fetuses are being aborted, well that's just too bad. The Constitution does not protect you against feeling bad.
And that's the whole issue regarding evangelical Christians. The Constitution grants us as human adults rights that children and fetuses don't share. Even the bible makes that distinction. You may disagree with which rights a fetus ought to share, but your disagreement does not give you the right to force compliance on those who disagree with you.
According to polls about half of Americans believe that abortion is ok, at least under some circumstances. I personally believe abortion should be unrestricted by law under any circumstance as long as the fetus is not yet viable. And my opinion is just as valid as yours. More importantly, my opinion does not restrict your rights not to have an abortion. Can you give women the same promise?