(Mishnah): If two men were Mekadesh two women, and at the time of Chupah they switched wives, they are liable for Eshes Ish;

If they are brothers, they are liable also for Eshes Ach. If the women are sisters, they are liable also for Achos Ishto. If they were Nidos, they are liable also for Nidah;

All of them, we separate [each woman from her husband] for three months, lest she is pregnant (from the other man. Without separation, we would not know who is the father of children born within nine months.) If the women are minors, who cannot give birth, we return them [to their husbands] immediately;

If they were Kohanos, they are disqualified from Kehunah.

(Gemara): If he had Bi'ah with the second [woman to become Mekudeshes], he is liable twice [in addition to Eshes Ish] - for Eshes Ach, and Ishah Al Achosah (Achos Ishto. This opinion holds that the one who had Bi'ah with the first is liable only for Eshes Ish, for Ein Isur Chal Al Isur, even if the latter Isur is Kolel or Mosif; R. Chiyah's Beraisa below disagrees - SEFER NIR.)

(R. Chiyah - Beraisa): Sometimes [in all, the four people are liable] four [Chata'os], sometimes eight, sometimes 12, and sometimes 16;

They are liable for Eshes Ish - this [couple] is liable two (one each), and this [couple] is liable two;

If the men were brothers, [they are liable also] for Eshes Ach - [in all] this [couple] is liable four (two each), and this is liable four;

If the women were sisters, [they are liable also] for Ishah Al Achosah - this [couple] is liable six, and this is liable six;

If they were Nidos, [they are liable also] for Nidah - this is liable eight, and this is liable eight.

If the men were minors and the women were adults, they are exempt from all of them. (The Kidushin was invalid. If the men were less than nine, it is not called Bi'ah, so they are exempt even for Nidah.)

If the men were adults and the women were minors, they are liable two, [each man is liable once] for Nidah. (The Kidushin was invalid, for a minor cannot be Mekadesh herself.)

[In this case] if [the girls'] father was Mekadesh them, they are liable eight (each man is liable for all four Isurim).

If one man was an adult and one was a minor [and both women were adults], the woman who had Bi'ah with the minor is liable, for she is the adult's wife. The woman who had Bi'ah with the adult is exempt [for Eshes Ish , for she is the minor's 'wife' (i.e. she is single, for a minor cannot be Mekadesh).

(R. Ba citing R. Yirmeyah): One who was raped need not wait three months.

Question (Mishnah): We separate them for three months, lest they are pregnant. If they were not proper to give birth, we return them immediately.

Answer: Here is different, due to fixing the child (if she does not wait, and she gives birth within nine months, the child is a Safek Mamzer. R. Yirmeyah was lenient for a single woman. Therefore, he did not mention returning her to her husband - BIRKEI YOSEF EH 13:3, OHR YAKOV.)

(Mishnah): If they were Kohanos, they are disqualified from Kehunah.

Inference (R. Yosi): Ones disqualifies from Kehunah, like an Eshes Ish (Eshes Kohen is disqualified even b'Ones. Even if her husband is a Yisrael, she is forbidden permanently to Kehunah -HA'GAON RAV C. KANIEVSKY, SHLITA.)