Resources for Yevamos daf 67

1.      The גמרא brings two possibilities as to why an עובר can't be מאכיל. One possibility is עובר במעי זרה זר הוא and the other is ילוד מאכיל, שאינו ילוד אינו מאכיל. The גמרא asks a question against the מ"ד that says the reason of ילוד מאכיל and doesn’t have an answer. One would think that would mean the הלכה would follow the reason of עובר במעי זרה זר הוא. Nonetheless, the גמרא on עמוד ב only quotes the reason of ילוד מאכיל. תוספות in ד"ה למאי points out that everyone agrees to the reason of ילוד מאכיל in regards to why the wife can’t eat, so it isn’t strange that the גמרא on עמוד ב quoted that reason. The גמרא’s question was only was slaves don’t eat. The רמב"ם in הלכות תרומות פּרק ח׳ הל׳ ד only brings the reason of ילוד מאכיל even for slaves. The כסף משנה there explains that this is because theרמב"ם  holds that everyone agrees that according to the רבנן (who we pasken like) the only reason is because of ילוד מאכיל. The גמרא brings a נפקא מינה between the two reasons of עובר במעי זרה זר הוא and ילוד מאכיל in a case of בת כהן לכהן. However, the differences are not limited to that case. There is a famous question of whether a wife of a כהן is allowed to walk into a cemetery when she is pregnant. The issue is that she may be carrying a boy כהן  and you aren’t allowed to be מטמא  a כהן . The רוקח says she is allowed to go because of ספק ספיקא: perhaps the child will be a girl who is allowed to go into a cemetery. Even if it is a boy, perhaps it will be a נפל. The קובץ שיעורים in חלק ב סימן מ"א brings that many ask a glaring question on this רוקח: you shouldn’t need a ספק ספיקא since עובר במעי אמו זר הוא in which case the child is not a כהן at all! It would seem the רוקח held like the reason of ילוד מאכיל and not עובר במעי אמו זר הוא. However, the קובץ שיעורים does not say that but rather answers that we need the ספק ספיקא for the case of a כהנת married to a כהן where the fetus is not considered a זר since it is a כהן from both parents. The חתם סופר in שו"ת חתם סופר יו"ד סימן שנ"ד says that even in the case where the mother is a כהנת there should still be no איסור to go in a cemetery since if you hold עובר במעי זרה זר הוא is based on עובר ירך אמו then it means the baby is like a limb of the mother. If the כהנת mother can go into a cemetery, so can the fetus. The חידושי הגרי"ז disagrees entirely and holds that עובר בעי זבה זב הוא doesn’t mean it is literally a זר. Rather it only relevant to the הלכה of eating תרומה.  

2.      The גמרא says that the slaves of the fetus cannot eat תרומה even if there are other brothers alive because of the חלק of the fetus which can’t be מאכיל בתרומה. The פּני יהושע in גיטין דף מ"ב ע"ב proves from our גמרא that if a ישראל and a כהן are partners in an עבד the עבד cannot eat תרומה even on the day he is working for the כהן because the ישראל has a portion in the עבד. However, he is דוחה this proof since perhaps our גמרא that says the חלק of the fetus in the עבד is מעכב the slave from eating is because it is possible the entire עבד may end up being in the חלק owned by the fetus, but if it was a שותפות then it could eat תרומה because of the other brothers. The truth is רש"י in ד"ה עבדי צאן ברזל says exactly that (that the issue is because the entire עבד may go to the עובר), and the רשב"א there asks on רש"י how he could say that when it is clear that even if all the brothers divided the slave he still couldn’t eat תרומה because of the fetus’s חלק.