(Mishnah) Question: What (Isur between the parents) causes the child to be a Mamzer?

Answer #1 (R. Akiva): It is when they are She'er (relatives) forbidden to each other by a Lav;

Answer #2 (Shimon ha'Temani): It is when there is Kares (for Bi'ah).

The Halachah follows him.

Answer #3 (R. Yehoshua): It is whenever there is Misas Beis Din.

(Mishnah - Ben Azai): I found a scroll of lineage in Yerushalayim that said 'Ploni is a Mamzer from a married woman', to fulfill R. Yehoshua's words.

(Gemara - R. Yosi ben Chaninah): All of them learn from Eshes Av - "Lo Yikach Ish Es Eshes Aviv v'Lo Yegaleh Kenaf Aviv" (and afterwards the Torah forbids a Mamzer);

R. Akiva expounds, just like Eshes Aviv, a Lav forbids Bi'ah, and the child is a Mamzer, also any [Bi'ah] that a Lav forbids, the child is a Mamzer.

Question: A widow to a Kohen Gadol [a Lav forbids Bi'ah, and the child is not a Mamzer]!

Answer: There is different, for [the Torah] explicitly said ["v'Lo Yechalel", to teach that the child is] a Chalal [and not a Mamzer].

Shimon ha'Temani expounds, just like Eshes Aviv, one is liable for her Kares bi'Ydei Shamayim, and the child is a Mamzer, also any woman for whom one is liable Kares bi'Ydei Shamayim, the child is a Mamzer.

Question: A Nidah [one is liable for her Kares bi'Ydei Shamayim, and the child is not a Mamzer]!

Answer: There is different, for it is not written about her "She'er Basar" (the Isur is not because she is a relative, therefore the child is not a Mamzer).

R. Yehoshua expounds, just like Eshes Aviv, one is liable for her Misas Beis Din, and the child is a Mamzer, also any woman for which one is liable Misas Beis Din, the child is a Mamzer.

Even though R. Yehoshua says that one who had Bi'ah with his sister, the child is Kosher (not a Mamzer), he agrees that if the child is female, she is Pasul from Kehunah.

Even though R. Shimon ben Yehudah said in the name of R. Shimon, that if a Nochri or slave had Bi'ah with a Bas Yisrael, the child is Kosher (not a Mamzer), he agrees that if the child is female, she is Pasul from Kehunah.

A man came in front of Rav. He said, because that man's (i.e. my) mother gave birth from a Nochri, [what is my status]? Rav said, [you are] Kosher.

Rav Chama bar Gurya (to the man): While your legs are still weary [from traveling, leave], before Shmuel comes and disqualifies you. (CHESHEK SHLOMO - this was Shmuel's region; Rav was unaware.)

Even though Rav says that if a Nochri or slave had Bi'ah with a Bas Yisrael, the child is Kosher, he agrees that if the child is female, she is Pasul from Kehunah.

Question: Why did they say that the Halachah follows R. Shimon ha'Temani?

Answer (R. Yosi bei R. Chanina): It is because in a place where all of the Arayos are included (a Hekesh equates them) for Kares, Eshes Av was taught specifically to teach about Mamzer.

Question: R. Yosi bei R. Chanina contradicts himself! There he learns from the Klal, and here he learns from the Prat!

(Beraisa) Suggestion: [One brings a Korban Chatas for transgressing] "Mitzvos Hash-m" - perhaps this includes one who eats vermin!

Rejection: You learn as follows. It says here "me'Einei", and it says there [about idolatry] "me'Einei". Just like Einei said there is something for which one is liable Chatas for Shogeg and Kares for Mezid, also Einei said here is something for which one is liable Chatas for Shogeg and Kares for Mezid.

Suggestion: Perhaps just like Einei said there is something that has Misas Beis Din, also Einei said here is something that has Misas Beis Din!

Rejection (R. Yosi bei R. Chaninah): In a place where idolatry was singled out to teach about [Korban for] Chayavei Kerisus, Misah was not taught with it, only Kares was taught. However, Misah comes from (was taught) elsewhere.

Repeat of Question: R. Yosi bei R. Chanina contradicts himself! There he learns from the Klal (Kares, which applies to all Arayos. He does not learn from the Prat (Eshes Av - only a Lav is written about it there)), and here he learns from the Prat (the punishment mentioned for idolatry there)!

Answer: There, all the Aveiros were included for Korban. Idolatry was singled out to teach about those that are Chayav Korban;

Can you say here that all the Arayos were included for Mamzer, and Eshes Av was singled out to teach about a Mamzer?! (Mamzer is written only there. We learn other Arayos only from the Hekesh, which is limited to Chayavei Kerisus.)