This language seems to suggest that the anchor baby will in fact cement the parents' right to stay:

Section 3304(d)(2)(A)(iii)

(2) HARDSHIP EXCEPTION.--
(A) IN GENERAL.--The Secretary of Homeland Security may, in the Secretary's discretion, remove the conditional status of an alien if the alien--
(i) satisfies the requirements of subparagraphs (A), (B), and (C) of paragraph (1);
(ii) demonstrates compelling circumstances for the inability to complete the requirements described in paragraph (1)(D); and
(iii) demonstrates that the alien's removal from the United States would result in exceptional and extremely unusual hardship to the alien or the alien's spouse, parent, or child who is a citizen or a lawful permanent resident of the United States.