Is there a moral difference between killing a newly born baby and having an abortion? To be consistent, do we have to say either abortion/infanticide is morally wrong OR that abortion/killing a newborn can be morally permitted if the circumstances are right?

The view that Matthew articulates--that the moment of birth is not morally significant in a way affects deeply the moral status of the newborn infant--is a popular one, but it has been challenged by some. For example, the feminist philosopher Mary Anne Warren argues that birth is morally significant in virtue of the newborn's expanded social relationships. To say that newborns have a different moral status than nearly-borns does not mean that late-term fetuses ought not to be protected from harm -- but Warren's line of thought might provide a philosophical basis for concluding that newborn infants and late-term fetuses are not entitled to exactly the same degree of legal protection. To answer your question more directly: If there is a substantive question about whether newborns and late-term fetuses have significantly different moral status, there is even a stronger case to be made that there are big differences in the moral status between newborns and fetuses that can be legally aborted. If...