For me it is all about what life is. Life is a process, a series of incremental stages that are seamlessly joined together from the moment the sperm and egg merge till the last neuron fires off its signal and the brain goes dark. You can't really segment the string that binds all those moments together in anything other than a completely arbitrary way. I love my daughter more than life, but I could make the argument that she isn't even human at this point in her development. Physically, mentally she is as unlike me as she is like me... yet clearly aborting someone in the 33rd trimester is not on the table.