Dear Avraham,

I was not able to find a Teshuvah in the Chasam Sofer -- or, for that matter, anywhere else -- that deals with your question of what to call a step parent. However, there is a Teshuvah of the Chasam Sofer (OC 164) that deals with the question of whether an adopted child is obligated to say Kadish for his deceased adopted parent. The answer is that he should, but that his obligation is less than that of someone saying Kadish for a biological parent. Rav Shlomo Zalman Auerbach zt'l seems to have had the same opinion (see Halichos Shlomo, Tefilah, 18:14). He says that even though he should say Kadish, he is not a real Avel (mourner) and is not exempt from Torah study during the Shivah.

What seems to follow is that an adopted child does not have a bona fide Mitzvah of Kibud Av v'Em but does have an obligation to honor his adoptive parent out of Hakaras ha'Tov. (See Sefer Yalkut Yosef, Kibud Av v'Em, ch. 7, section 8, who writes this explicitly.) The same would apply to a step-parent, who also deserves Hakaras ha'Tov for helping to raise the child. Therefore, all of the Dinim of Kibud Av v'Em (or Morah) -- including the Isur of calling a parent by his or her first name -- should apply to the adopted child and to the step child.

If, however, the step parent did not help raise the child, then this reasoning would not apply (and, in fact, the step parent is probably not called "stepfather" or "stepmother" according to proper English usage, but rather just the parent's spouse). However, even in this case there is an obligation of respect that flows from the child's obligation to respect his biological parent. Rav Moshe Sternbuch told me that if one's bioligical parent insists on his or her spouse being called "mom" or "dad" then one should honor that wish.

Kol Tuv,

Yonasan Sigler

This is not a Psak Halachah