To the ancients, the father was considered to be the true parent. Aristotle, in On the Generation of Animals, said that the father implanted the fetus (or "homunculus") while the mother merely nurtured it and gave it a place to grow. Thus, "father" gave an image with a closer meaning to "real parent" than "mother" would.

 In Aeschylus' play, The Eumenides, the god Hermes says "The mother is not the parent of the child which is called hers. She is the nurse who tends the growth of the young seed planted by its true parent, the male."

The image Jesus was purveying was "true parent", not "male parent".