I answer that, It is
essential to Baptism that some part of the body of the
person baptized be in some way washed with water, since Baptism is a kind of washing, as stated above (66, 1). But an infant’s body, before being born from the womb, can nowise be washed with water; unless perchance it be said that the baptismal water, with which the mother’s body is washed, reaches the child while yet in its mother’s womb. But this is impossible: both because the child’s
soul, to the sanctification of which Baptism is ordained, is distinct from the
soul of the mother; and because the body of the animated infant is already formed, and consequently distinct from the body of the mother. Therefore the Baptism which the mother receives does not overflow on to the child which is in her womb. Hence
Augustine says (Cont. Julian. vi): “If what is conceived within a mother belonged to her body, so as to be considered a part thereof, we should not baptize an infant whose mother, through danger of death, was
baptized while she bore it in her womb. Since, then, it,” i.e. the infant, “is
baptized, it certainly did not belong to the mother’s body while it was in the womb.” It follows, therefore, that a child can nowise be
baptized while in its mother’s womb.
