5 But further, and in addition to what has been said, the question occurs, Did their mother, when she beheld the angels, bring forth the seed all at once, or only one by one [in succession]? If she brought forth the whole simultaneously and at once, that which was thus produced cannot now be of an infantile character: its descent, therefore, into those men who now exist must be superfluous. But if one by one, then she did not form her conception according to the figure of those angels whom she beheld; for, contemplating them all together, and once for all, so as to conceive by them, she ought to have brought forth once for all the offspring of those from whose forms she had once for all conceived.
Source: Adversus haereses (New Advent)