לזכות אבי מורי ואמי מורתי שיחיו
ולע"נ הוריהם ז"ל
Says the Rambam [Melachim 10-3]:
בן נח שנתגייר ומל וטבל ואח"כ רצה לחזור מאחרי ה' ולהיות גר תושב בלבד כשהיה מקודם אין שומעין לו אלא יהיה כישראל לכל דבר או יהרג ואם היה קטן כשהטבילוהו בית דין יכול למחות בשעה שיגדיל ויהיה גר תושב בלבד וכיון שלא מיחה בשעתו שוב אינו מוחה אלא הרי הוא גר צדק לפיכך אם בא ישראל על קטנה שהטבילוה בית דין כסף כתובתה או קנס אונס או מפתה יהיה הכל תחת יד בית דין עד שתגדיל ולא תמחה בגירות שמא תטול ותגדיל ותמחה ונמצאת זו אוכלת בגיותה מעות שאין לה זכות בהן אלא בדיני ישראל:
A gentile who converted, was circumcised, and immersed in the mikveh, and, afterwards, decided to forsake God and revert to his previous status as a resident alien is not granted permission to do so. Rather, he must remain as an Israelite in all matters or be executed.
If he was a minor and immersed by the court, he may repudiate his conversion when he attains adulthood and assume the status of a resident alien alone. However, if he does not object as soon as he attains majority, he is no longer given the opportunity to object and his status is that of a righteous convert.
Therefore, if a Jew has relations with a girl below the age of majority who was immersed in the mikveh by a court, the money due her as payment of her kesubah or as a fine for raping her or seducing her is placed in the custody of the court until she attains majority and does not repudiate her conversion. This step is taken lest she take the money, attain adulthood, and then, repudiate her conversion. Thus, she would derive benefit as a gentile from monies to which she is only entitled according to Jewish law.
The Rambam contrasts a קטן and a גדול. What a גדול may not do a קטן may do [i.e. repudiate his conversion]. This is a WONDER!! When the Rambam says that there is no repudiating geirus, that applies equally to גדולים AND קטנים. The capacity of a קטן to repudiate his [or her] conversion [כתובות י"א] is because his geirus stems from the din of זכין לאדם שלא בפניו - We are allowed to grant a zchus to a person even without his knowledge [and we also do so for a קטן who lacks דעת]. When he comes of age and reveals that to his mind conversion is no zchus, he may retract and thereby the geirus is retroactively nullified [בטלה למפרע] as we see in the Rashba [Kiddushin 23a and see Chasam Sofer in Ksubos]. But what has that got to do with the issue of a גדול nullifying his geirus from here on in [מכאן ולהבא]?? It is a totally different din!
Moreover when discussing the din of childhood conversion [Isurei Biah 3-7], the Rambam doesn't even mention the din of מחאה [protesting the earlier proceedings - see the Magid Mishna there]?! The Ran in Ksubos alluded to this issue and said that the Rambam wrote the din of Rav Huna that we may immerse a גר קטן with the approval of a Beis Din in הלכות איסורי ביאה while he wrote Rav Yosef's din of the right of the קטן to protest in הלכות מלכים but that raises the issue [hints the Ran] of why the Rambam didn't codify the דין מחאה in הלכות איסורי ביאה where it belongs?! [See חתם סופר יו"ד רנ"ג].
It MUST BE that the din of מחאה relates to the din of a גדול repudiating his geirus which is why the Rambam quotes it here. But that, again, is a VUNDER because these are two conceptually different dinim. A קטן who protests undoes the geirus from the root because he shows that there was no זכין while the גדול who repudiates his geirus only does so from here on in and it has nothing to do with זכין?!
