Interesting points. Remember when it comes to law, however, the practicality of objective enforcement sometimes means setting a hard number within a continuum that doesn't necessary apply logically to every situation. Take for instance age cut-offs for emancipation, drinking, driving, marriage, etc.
So the Court said that somewhere during fetal development the qualities develop for which the law should recognize any rights. They don't tell us what those qualities are, or exactly how they can get it from the Constitution, but they know that 12 weeks gestation is about the time it usually happens.
Good points ... and the law is the original reason for this thread. We are about to have a national deabte over banning human cloning at this time. As offered in the essay starting this thread, therapeutic cloning is cannibalism of individual human lives conceived for the purpose of harvesting their body parts. In order to have a truthful debate, some parameters must be hammered out. Jennyp offered the notion of form and function as the hallmark definitions for the different ages along the timeline/continuum of individual human life. Others have added the age they would consider relevant for defining 'worthy of legal protection'. Abortion enters the issues when/if cloned embryos are conceived and implanted, then killed and harvested for their body parts.
I offer that termination from a woman's life supporting body need not be the only application of the term abortion, for the support offered to cloned, alive, developing individual humans, though outside a human body, is life support, therefore to consciously remove life support (especially for an individual human life purposely conceived in vitro) is to abort an already existing individual life.