Reason, not rationalization, is the proper use of the intellect.
However, it is entirely dependent on its mother, who has the perfect right to evict the perceived trespasser at any time. Just because she had sex does not mean that she has made a contract with her baby to carry it to term. To get all Rothbardian on you, how on earth can a very young fetus enter into a legally-enforceable contract?
By your logic, then, if I tell someone e can come into my house, then say e is trespassing and kill em, it's not a problem? Just because I voluntarily did something that was at least likely to result in someone besides myself being inside my house, does not mean I made a contract to treat em like a guest? As for a legally-enforceable contract, this logic would seem to apply to a child of any age as well; so apparently you would condone killing (or at least evicting) children, on the grounds that as non-adults they cannot make contracts?
This tortured "logic" is a good example why much "libertarian" discourse ends up being ridiculous. A "libertarianism" which finds such convoluted rationalizations to break agreements is not truly libertarian, and truly deserves the common confusion with "libertine" in the public mind. Freedom without responsibility is simply license. License is not freedom; it is actually slavery, if not to an external master then certainly to ones own uncontrolled and selfish impulses.
Like most other human acts, sex has consequences. An adult, when acting, considers the consequences, including the possible consequences. I always wear a helmet when riding my bicycle; I know others who do not. I do not favor helmet laws; but I also do not consider a non-helmet rider whose head gets broken a "victim". Again, women seem to want to have it both ways: they want the "rights" of adults, and full citizens, without the responsibilities. Which in itself demonstrates that they are not yet adults.
I'm not saying Dr. Paul would support this synthesis. I'm quite sure he would not. But it seems to be to be as close a compromise between the rights of both mother and baby as can be imagined.
That's just the problem, this deification of "compromise". In fact, in matters of principle there is no "compromise": either something is right, or it is wrong. "Compromise" is the hobgoblin of little minds determined to rationalize a way to what they want, regardless of principle. Take a gallon of pure spring water; pour in a thimble of urine; what do you have? A "compromise".
Funny, you'd think women might be able to understand this, given that "there is no such thing as being a little bit pregnant". But apparently many (most?) of them don't.
"The world’s black and white, good and bad, no matter what you hear. The people who say it isn’t have already chosen black." --Amos Walker