Question: Is there a problem to feed young children before Kiddush?
Discussion: The Shulchan Aruch (Orach Chayim Siman 269 se’if 1) writes that the custom is to recite Kiddush in Shul [on Friday night]. The Shulchan Aruch continues and says that the individual making Kiddush should not drink from the wine; rather he should give it to a minor to drink. The reason for this is because Kiddush has to be recited in a place where one will eat a meal (kiddush b’mokom se’udo), and since the person making Kiddush will (generally) not be eating in Shul, he has not fulfilled the mitzvah of Kiddush since he does not eat in the place where he makes Kiddush and thus were he to drink the Kiddush wine it is considered as if he has drunk before Kiddush, which is prohibited.
It is clear from the context of the Shulchan Aruch that although there is an issue for an adult (i.e. the person making Kiddush) to drink the wine, regarding a minor we are lenient and allow him to drink despite the apparent prohibition (of drinking before Kiddush). The Shulchan Aruch does not elaborate on the reason for the permissibility of a minor to drink Kiddush wine.
The Magen Avraham (s.k. 1) asks that it is forbidden to feed a minor a forbidden food item? Based on his reference to Siman 343 it he appears to be asking from the prohibition of “sofinon” – that it is prohibited to feed a minor (of any age) a forbidden food item. (Sofinon is not exclusive to food issurim; it applies to any situation where one directly causes a child to transgress an issur, e.g. placing a minor who is a Kohen in the same building as a dead body is also forbidden because of sofinon.)
The Magen Avraham (ibid) brings several different approaches to answer the question:
1) The first answer he brings is that sofinon only applies to a “lav” (i.e. a lo sa’ase). Kiddush, he writes is merely an aseh. The Machtzis Hashekel (ibid) explains that the Magen Avraham means to say that the prohibition of eating before Kiddush is “only” Rabbinical, and is certainly not forbidden min hatorah [therefore it is permitted to give a minor the Kiddush wine].
2) The Magen Avraham continues and says that according to the opinions quoted in Siman 343 that maintain that sofinon also applies to an issur d’rabonon we must say that since there exists an opinion who maintains that there is not a prohibition to drink before Kiddush, although this lone opinion is not followed, for a minor it is permitted [to rely on this lone opinion]
3) The next explanation brought by the Magen Avraham in the name of the Beis Yosef is that since there is no alternative it is permitted (the Levushei S’rod explains that were no one to drink, the brochos of Kiddush will be l’vatolo).
4) The final approach of the Magen Avraham is that regarding issurim that are necessary for the child’s developments, sofinon is not applicable, if the issur in question is not intrinsic (such as treifos) but time dependent. This permissibility only applies to issurei d’rabonon.
The Magen Avraham also mentions that it is similarly permitted to feed young children on Shabbos morning before Kiddush, and it is forbidden to afflict them [by withholding from them food].
The Mishna Berura (Siman 269 s.k. 1) quotes the Magen Avraham regarding the permissibility to feed a minor Kiddush wine in Shul.
Conclusion: It is permitted to feed young children before Kiddush; the source for this is the Shulchan Aruch in Siman 269. (The Magen Avraham ibid discusses at length the reason for this.)