I couldn't resist forwarding the link to the article to my Foreign Service sister, and she spontaneously gave quite a lengthy reply, including:
"Actually, we can't be sure from the facts in the article whether the mother would have conferred U.S. citizenship even if the children were born from her eggs. She is wrong in believing that children born of U.S. citizens are automatically entitled to U.S. citizenship. Citizenship and nationality law is different for children born in or out of wedlock, it depends on year of birth, there are residency requirements for the U.S. citizen parent, and so forth, and the determinations can be rather complex, especially if documenting exact number of days spent in the U.S. is necessary. The children would have received
citizenship by jus terra if she had come to the U.S. to give birth, but quite
possibly she did not know there would be a problem if she did not."
Maggie (in VA)