Appeal from an order of the Family Court, Otsego County, entered April 16, 1973, which adjudged appellant to be the father of the petitioner’s child. The petition in this proceeding alleged but a single occasion upon which petitioner engaged in acts of sexual intercourse with respondent and specified the date thereof as March 4, 1972. Although a child was born to petitioner on November 17, 1972, indicating a gestation period of only 259 days, the applicable hospital records are devoid of any reference to a premature birth. The results of a blood test were inconclusive. Both parties agreed that there had been only one instance when they had engaged in sexual relations, but neither could identify or substantiate the precise date of that incident. Acceptance of the earliest possible date developed from the range of testimony on this point would still fail to significantly lengthen the foregoing period of gestation. Appellant has at least raised the possibility of access by another, while petitioner wholly failed to adduce any medical proof explaining the apparent shortness of her gestation period from the generally accepted norm (compare Baranowski v. Luciano, 23 A D 2d 815, with Matter of Kiamos v. Chiladakis, 25 A D 2d 647). Under these circumstances, we cannot say that petitioner met her burden of proof establishing appellant to be the father of her child by clear, convincing and entirely satisfactory evidence (Matter of Lopez v. Sanchez, 34 N Y 2d 662). Order reversed, on the law and the facts, and matter remitted for further proceedings not inconsistent herewith, without costs. Kane, Main and Reynolds, JJ., concur; Herlihy, P. J., and Sweeney, J., dissent and vote to affirm in a memorandum by Herlihy, P. J. Herlihy, P. J. (dissenting): We dissent. Under the facts and circumstances of this case, it was unnecessary for the petitioner to adduce expert medical testimony to prove the prematurity of her child.