I have several questions about step-relations.
Is one halachically allowed to attend the marriage between a parent and step-parent to be? I’ve heard it’s forbidden for the children to attend the wedding. Is there any basis for this?
May a bar mitzva be called to the Torah as the son of his step-father, or must he be called as the son of his real father’s name?
Is it halachically permissible for step-siblings to marry each other?
In the past, these questions were usually raised as a result of a spouse or parent passing away which is fortunately less common nowadays. But given the increase in divorce rate, these questions have become unfortunately very much in-step with the times.
Regarding not attending a parent’s re-marriage, the widespread custom is that children do not attend a parent’s second marriage. One logical explanation is that the children’s presence is a reminder of the previous spouse, and could thus mar the joy of the occasion for either of the newly-weds.
Rabbi Yosef Shalom Elyashiv, ztz”l gave the following explanation: Children have an obligation to respect their parents even after the parents have passed away (Sh.A., Y.D. 240:9). Attending the marriage of a surviving parent would be disrespectful to the deceased parent.
It seems to me that this reasoning would certainly apply when the other parent is still alive. And in such a case (except for extreme circumstances) precedence should be given to the parent who objects that the child participate over the one who is getting married and wants him to be there. This is because in the one case he’d be causing anguish while in the other he’s only detracting from joy.
However, in cases where, for whatever reason, one could estimate that attending the wedding would not upset the other parent (living or deceased) or the step-parent to be, it would probably be halachically permitted.
Regarding calling a step-son by the name of his step-father, generally this should not be done, even if the father is no longer alive and died when the son was very young. For one, biologically, it’s not true. In addition, there’s also a consideration of honor for the natural father even after his death. And even though a person must honor his step-parent, this doesn’t exempt him from the Divine decree to honor his real father.
Rabbi Moshe Sternbuch shlita, cited a responsa of the Yaavitz that in a case where the father is still alive, but there is absolutely no contact between the child and his father, then it is permissible to call the child to the Torah using his step-father’s name. However, he qualified that if there is even the most minimal contact between the father and his son, then the son should use his biological father’s name.
Marriage between a step-brother and a step-sister is permitted, and this is the accepted practice (Sh.A., E.H. 15:11). For example, the Chafetz Chaim, Rabbi Yisrael Meir Kagan, married his mother’s husband’s daughter.
According to Tzava’at Rabbi Yehudah HaChasid, step-siblings should not marry. However, this ruling seems not to have been accepted even by those who generally adhere to the other rulings of Tzava’at Rabbi Yehudah HaChasid (Sefer Shmirat Haguf v’Hanefesh 178).