If I am understanding Becca correctly, you believe that the unborn is human with rights, but are not sure.  If you thought there was a homeless man sleeping in a condemned building, but were not sure, would you stand by while it was being demolished?
And your argument that women will have abortions anyway so just let them - how would that fly with child abusers?  They will abuse anyway, let the decision be left to their moral conscience?  
And the status of a fetus is subjective opinion?  You might check that with solid facts of science, even a decent embryology textbook "The Developing Human: clinically Oriented Embryology": we are unique humans whose development started at fertilization - living and growing, with unique DNA, developing organs in 3 weeks, a beating heart in 18 days, facial features at 4 weeks, and so much more that is undeniably human - even unique fingerprints at 10 weeks.  At this time, even a child will recognize a 3d ultrasound a baby.  We all were unborn once.