Who May Not Serve As The Shushbinim-
1. A couple that is divorced should not serve together as the shushbinim. (Sefer Mates Yado 132 and Sefer Yivakshu Mipihu page 528)
2. Harav Yosef Shalom Elyashiv zt”l rules that a divorced couple may serve as the shushbinim if the men are escorting the chosson and the women are escorting the kallah, since the divorced couple will not be escorting the chosson or kallah together (Yivakshu Mipihu page 526).
3. Harav Gavriel Zinner shlit”a writes that if ruling stringently will cause an argument, then one may allow for them to serve as the shushbinim. (Netai Gavriel Marriage 14:7)
4. Harav Moshe Feinstein zt”l (Igros Moshe Y.D. 3:106) and Harav Yosef Shalom Elyashiv zt”l (Yevakshu Mipihu page 536) both feel that if the chosson or kallah have a father who is a non-Jew he may not serve as a member of the shushbinim. Harav Moshe explains that if a non-Jewish man who lived with a Jewish woman is allowed to walk down the aisle, it may appear as if such a union is permitted.
5. According to Harav Moshe’s reasoning, it would seem that a convert may be escorted down the aisle by his non-Jewish parents, since we have no objection to two non-Jews being married. However, Harav Yosef Shalom Elyashiv zt”l rules that the parents of a convert should not serve as the Shushbinim. Rather, they should be given a different honor. For practical halacha, a rabbi should be consulted.
6. The poskim cite a custom that if a man or woman are currently in a second marriage (i.e. a parent and stepparent of the chosson or kallah), they should not serve as the shushbinim. (Shulchan Haezer 7:4:1, Ezer Mekodesh E.H. 68, Levushei Mordechai 22 and Yivakshu Mipihu page 530)
7. Harav Moshe Shternbuch shlit”a (Teshuvos V’Hanhagos 2:652) maintains that if the chosson or kallah were raised by their step-parent, the step-parent may escort him down the aisle. He adds that if preventing a step-parent from walking down the aisle will cause a fight, then one may rule leniently and allow it.
8. The Shulchan Haezer (ibid.) writes that if the chosson or kallah are a product of the second marriage, then the parents may serve as the shushbinim. The Rav of Debreczin zt”l agrees with the ruling of the Shulchan Haezer (Beer Moshe 3:184). This is also the custom of Vizhnitz Chassidim (Netai Gavriel ibid.). Other poskim, however, rule stringently (Netai Gavriel ibid. and Chelkas Yaakov cited in Beer Moshe ibid.).
9. Some poskim feel that a couple that is childless should not serve as the shushbinim (Shulchan Haezer ibid.).
10. The Rav of Debreczin zt”l explains that if the couple is young and still capable of having children, and they just have not been blessed yet, they may serve as the shushbinim. If however, the couple feels uneasy about serving as the shushbinim, then they should refrain from doing so.
11. Harav Yosef Shalom Elyashiv zt”l maintains that a childless couple may always serve as the shushbinim (Yivakshu Mipihu page 538). For normative halacha, a rabbi should be consulted.
12. The Shulchan Haezer and Harav Yosef Shalom Elyashiv zt”l write that although many people feel that a pregnant woman cannot escort the kallah down the aisle, this ruling is unfounded and it is actually permitted.
13. However, many poskim feel that if a pregnant woman were to serve as a member of the shushbinim, it may cause an ayin hara (evil eye) and therefore should be avoided. (see Nisuin K’Hilchosom page 440)
14. The Rav of Debreczin zt”l rules that there is only a concern of ayin hara once her pregnancy is visible to others. Before that point it would be permitted. This was also the view of the Rebbe of Munkatch zt”l (Haskama to Sefer Zocher Habris).
15. The custom of Chabad Chassidim (Sefer Haminhagim page 76) is that if the mother of either the chosson or kallah is pregnant, an additional married couple should be taken to circle the chosson under the chuppah.
16. Harav Gavriel Zinner shlit”a writes that if the mother of the chosson or kallah is pregnant and it will cause pain and strife if she does not escort her child down the aisle, then she may be allowed to do so. For normative halacha, a rabbi should be consulted.