Regardless of where we agree or disagree, there is no agreement in medicine, philosophy, or theology as to what stage of embryonic (or, later, fetal) development should be associated with the right to life. Some people argue it’s at the first sign of brain activity (presumably indicating some kind of consciousness), much as cessation of brain activity marks the end of life. Some believe it’s when the fetus is viable — in other words, when it could survive if born. Some believe it’s the moment the eggs is fertilized, although at this point the egg is still an egg, and nothing has really developed yet. Other people believe it’s when the egg is implanted, because many fertilized eggs never successfully implant. I include this link, not to convince you one way or another, but to show the very real disagreement about when human life begins. Much as you believe that science has backed up the idea of life-at-conception, pro-choice supporters believe that science has shown the opposite. Science can’t really do either, because the question touches on deeper beliefs about what life really is.

To some, the idea that something magical happens at the moment of conception isn’t much different to the idea that some religions still hold, particularly in the developing world, that birth control is a sin. And there are other grey areas as well, such as the question of IVF, which necessarily involves the destruction of fertilized embryos. There are other reasons people may support abortion choice as well, including the legacy of deaths from illegal abortions in the past. But whether we frame it as being about life or rights, I think it comes down to beliefs in the end.