
158 Mich. App. 702 (1987)
405 N.W.2d 147
STEIN
v.
SOUTHEASTERN MICHIGAN FAMILY PLANNING PROJECT, INC.
Docket No. 89020.
Michigan Court of Appeals.
Decided February 6, 1987.
Sommers, Schwartz, Silver & Schwartz, P.C. (by Jeffrey N. Shillman and Barbara A. Patek), for plaintiffs.
John D. O'Hair, Corporation Counsel, Glen H. Downs and Dean Koularas, Assistant Corporation Counsel, for Wayne County General Hospital.
Before: CYNAR, P.J., and J.H. GILLIS and D.F. WALSH, JJ.
PER CURIAM.
Plaintiffs, Catherine Stein, also known as Catherine Sudat, and her husband, Michael *703 Stein, appeal from a circuit court order granting summary disposition to defendant Wayne County General Hospital.
On the authority of Hyde v University of Michigan Bd of Regents, 426 Mich 223; 393 NW2d 847 (1986), we affirm the entry of summary disposition for defendant on plaintiffs' malpractice claim. The fact that defendant did not raise the "defense" of governmental immunity until after Ross v Consumers Power Co (On Rehearing), 420 Mich 567; 363 NW2d 641 (1984), was decided does not make the rules articulated in Ross inapplicable to this case. Plaintiffs' previously filed complaint alleged sufficient facts to raise a governmental immunity issue. Hyde, supra, p 236, n 7.
We have considered plaintiffs' arguments that granting immunity to public hospitals deprives patients of equal protection and due process. In Ross, supra, and Hyde, supra, the Supreme Court considered, and rejected, the public policy and fairness claims raised by plaintiffs concerning the substantive issue of immunity and the procedural issue of retroactivity. See, e.g., Ross, supra, pp 618-619, and Hyde, supra, pp 238-240, 244. In light of Ross and Hyde, plaintiffs' arguments should be addressed to the Supreme Court which, we are persuaded, would not find unconstitutional the disparate treatment of public and private hospitals. See Hyde, supra, p 244, n 15.
Plaintiffs challenge the denial of their motion to amend their complaint to allege defendant's breach of contract. The absence of a writing signed by an authorized representative of defendant and containing the essential terms of the alleged contract is fatal to plaintiffs' contract claim. MCL 566.132(g); MSA 26.922(g); Gilmore v O'Sullivan, 106 Mich App 35; 307 NW2d 695 (1981), lv den 413 Mich 851 (1982).
Affirmed.
