Michael Egnor pretty much demolishes this claim and a couple of others in a piece at Evolution News and Views. Here's part of Egnor's essay:
Contra Rosenau, there is a sharp biological distinction between a baby in the womb and a cancer. That sharp distinction holds at every stage of human development. A zygote/embryo/fetus is an individual member of the species Homo sapiens. A cancer cell/tumor is not an individual member of the species Homo sapiens. A cancerous tumor is a part of a human being that has lost growth regulation and replicates without normal inhibition. Dermoids (benign tumors) and HeLa cells (immortal cervical cancer cells grown in culture and widely used for experiments) are not human beings.It is surprising to me that anyone who holds such a lofty position in an organization given to the promotion of science, as Rosenau does, would affix his name to such an absurd assertion. Anyway, anyone who's interested in the abortion issue should read Egnor's entire essay. It's what the kids, I'm told, call a smackdown.
A cancer cell if unchecked will grow into a tumor which will kill the human being of which it is but a part. A human being at conception will mature to a newborn baby and to an adult. A cancer is biologically, physiologically, biochemically, morphologically, histologically, phylogenetically, teleologically, therapeutically, and morally different from an unborn child. Cancers should be excised, radiated, and eliminated with chemotherapy. Children in the womb should be nourished, loved, and delivered alive and healthy.
The question is not whether a zygote (or embryo or fetus) is a human being. He or she is. And the question is not whether a cancer is a human being. It is not. Both are uncontested rudimentary facts of biology. Any competent biologist can distinguish an unborn child from cancer. Any competent pathologist can distinguish an unborn child from cancer. Any competent obstetrician can distinguish an unborn child from cancer.
Yet Rosenau, Programs and Policy Director for the National Center for Science Education, finds that "that line is hard to draw."