An unmarried woman is about to give birth. She knows that she will have a son and does not want the natural father's name to be noted when the Mohel gives the child a name at the b'rit milah. What name should be given? (Dr. Peter Torren, Lafayette Hill, PA)
The matter has been dealt with repeatedly in the Halakhah, especially when the identity of the father was either unknown, or not revealed by the mother, or when he was an apostate. In the latter case, the Shulchan 'Arukh (OH 139:3) says that the name of the child's grandfather should be substituted for that of the father. This was done, in part, because calling the child merely by the name of the mother would at once testify to the fact that the son was not born into a normal family and thereby shame the mother in public.1
The cultural environment of our day, of course, has changed significantly, and many a woman would not mind at all to have it acknowledged publicly that her child was born extra-maritally, and therefore to mention only the mother's Hebrew name would be acceptable and sufficient. (This too has ample halakhic sanction.) However, no one knows at this point how the son will feel about this in later years, and so I would deem it advisable to add a patronymic to the child's name. Giving him the mother's father's name would be in accordance with halakhic tradition.
The same would apply if the actual father's name is unknown or if the father is a Gentile.
In sum, we suggest that the child be named XYZ, son of .... (grandfather's name) and ... (mother's name). If the woman does not wish to use her father's name, she may (according to talmudic precedent) choose the name of a much admired personality, biblical or other.
See the survey of this whole issue by Rabbi Solomon B. Freehof, Contemporary Reform Responsa, "Naming the Child of an Unmarried Mother," #20 pp. 91-97.)
If needed, please consult Abbreviations used in CCAR Responsa.