In Which I...

...ask for some non-Objectivist moral arguments.

I have a relatively easy time with things like abortion.  It requires, however, the attitude that nobody is entitled to you, your efforts, your nutrition; you are yours.

Are there any convincing and morally consistent arguments for abortion that can be raised by somebody who believes others -can- be entitled to you?  Specifically, an argument which is not dependent on ascientific beliefs like "A fetus isn't a human being entitled to any kind of legal protections."  (I'm not saying it's scientifically provable as false - it's simply outside the domain of science.  It's a philosophic or religious belief, however you choose to ascribe it.  And I'm entirely convinced it's a belief adopted for the specific purpose of validating abortion without considering the morality thereof.)

I've seen pseudo-pragmatist arguments, but these are always from people who make shit up in order to justify their positions.  And adoption is an alternative, and babies are in pretty much constant demand (although the prohibitively high costs of adoption should probably be examined), so the costs of raising a child aren't a convincing argument to me.

Basically, I'm looking for a broadly appealing argument which doesn't beg its own case, and which doesn't require specific and contentious philosophic or religious beliefs.  (Specific in this case meaning "Having absolutely no implications outside the matter of abortion.")

One example argument, which flies poorly with almost everybody, is that humanity is a net moral negative.  Essentially, if you believe the human race is morally obligated to go extinct.  Abortion is very easy to justify in that situation.  It satisfies everything except "Broadly appealing."