Kenneth G. Wilson (1923–). The Columbia Guide to Standard American English. 1993.
father (n., v.)
As a transitive verb father is Standard: He had fathered three children by the time he was twenty-five. The intransitive verb, usually as a gerund, fathering, is apparently fairly recent, perhaps an imitation of parenting and certainly on analogy with mothering. It is a low-frequency word of uncertain future, but it appears at present to be acceptable in all but the most conservative uses.
