The Christian dogma of virgin birth teaches that Mary, the mother of Jesus, remained a virgin, i.e., a virgo intacta, her entire life, before, during, and after the birth of her son. “The Christian belief is that Mary's virginity was never broken, neither at the time of the birth [in partu] nor before [ante partum], nor after [post partum].” The Jewish polemicists challenged this assertion on all three points.

The doctrine of the virgin conception was not attacked per se. The possibility that a woman might conceive with her virginity intact, though by means of normal fertilization, is an occurrence which is conceded in the Talmud. Nevertheless, the Jewish polemicists rejected the notion that God could become incarnate by impregnating a virgin and fathering an offspring who was, according to Christian doctrine, God Himself. Hence, the Jewish thinkers rarely offered arguments against the doctrine of Mary's virginity ante partum without reference to incarnation. Abraham Farissol expressed it this way:

The denial of incarnation was sufficient justification for rejection of the doctrine of Mary's virgin conception of Jesus.

The maintenance of the doctrine of Mary's virginity after Jesus’ birth, assuming that she had remained a virgin ante partum and in partu, was more an exegetical than a philosophical problem. Jewish polemicists, following the example of Christian dissenters, pointed out various New Testament passages which seemed to indicate that, after Jesus’ birth, Mary lived a normal married life, one that included sexual relations and the bearing of children. Since exegesis and not philosophical considerations was the major issue here, in the context of this study we may disregard the debate over Mary's virginity post partum.

One topic remains, then, that of the doctrine of virginity in partu, during the actual birth of Jesus. This belief was not taught explicitly in the New Testament, and it was not unanimously supported by the Church Fathers. By the time the Jewish polemicists criticized it, the perpetual virginity of Mary was a well-established doctrine; this, however, had not always been the case.