Human rights based on appearance?

Michael Gerson, opinionist for the Washington Post, writes about how public opinion hasn’t changed much over the last 40 years regarding support for abortion at different stages of development. He quotes Gallup:

A solid majority of Americans (61 percent) believe abortion should generally be legal in the first three months of pregnancy, while 31 percent disagree. However support drops off sharply, to 27 percent, for second-trimester abortions, and further still, to 14 percent, for third-trimester abortions

The solidity of support for killing younger unborn babies, draws into question the pro-life strategy that's been in place for decades. Arguing for waiting periods, for example, doesn't exactly make the case that unborn babies are human rights bearing individuals. Mr. Gerson states what I think accurately describes public sentiment:

An opinion this consistent and nearly universal must be based on something. The late political scientist James Q. Wilson gave the most persuasive explanation. In his 1994 essay, “On Abortion,” he argued bluntly that “people treat as human that which appears to be human; people treat as quasi-human that which appears quasi-human.” Sympathy, in his view, grows with resemblance.

The more the unborn baby looks like “us”, the less support there is for killing the baby. If this strikes you as shallow thinking, that’s because it is shallow thinking. Such thinking is exactly what racists believe: If you don’t look like us, you are subhuman without value.

Racism has been thoroughly discredited, because we recognize the vacuity of judging human rights based on appearance. Can we apply the same standard to the weak and vulnerable human beings in the womb?