Yevamos, Chapter 7, Mishnah 5. Our Mishnah deals with cohabitation that is not accompanied by kiddushin, and with the question of the power of such cohabitation to disqualify a woman from Terumah or to entitle her to eat it, and likewise with the power of the child born from it to disqualify or to entitle.
"Ha'ones veha'mefateh veha'shoteh - lo poslin velo ma'achilin" - the rapist, the seducer, and the shoteh (one who is not of sound mind) neither disqualify nor entitle:
A Yisrael who raped the daughter of a kohen, or who seduced her, and likewise one who is not of sound mind who cohabited with her - in all these cases there is no kiddushin, only cohabitation. Therefore the cohabitation does not disqualify her, and even though he is a Yisrael and she is the daughter of a kohen, she remains permitted to eat Terumah. And so too the reverse: if the one who cohabited with her is a kohen and she is the daughter of a Yisrael, these acts do not entitle her to eat Terumah, since there is no kiddushin here and she is not like a woman married to a kohen.
"Ve'im einan re'uyin lavo b'Yisrael - harei elu poslin" - and if they are not fit to enter the congregation of Israel, these do disqualify:
If the one who cohabited with her is not fit to enter the congregation of Israel, such as a mamzer, the cohabitation disqualifies her from Terumah, whether it was by rape, by seduction, or by one who is not of sound mind, since she has cohabited with someone who disqualifies her.
How so? A Yisrael who cohabited with the daughter of a kohen:
"Tochal biTerumah" - she may eat Terumah. Through cohabitation alone she is not disqualified, for this is not like kiddushin made with the Yisrael.
"Ibrah - lo sochal biTerumah" - if she became pregnant, she may not eat Terumah. Once she has conceived from him and is carrying the child of a Yisrael, she can no longer return to her father's house and eat Terumah.
"Nechtach ha'ubar b'me'eha - tochal" - if the fetus was cut up in her womb, she may eat. Once the fetus has been lost and she no longer has offspring from a Yisrael, she is like a woman who had cohabitation alone, and she returns to eating Terumah.
A kohen who cohabited with the daughter of a Yisrael:
"Lo sochal biTerumah" - she may not eat Terumah. The cohabitation with a kohen by itself is not enough to entitle her; there must be kiddushin or nisu'in.
"Ibrah - lo sochal" - if she became pregnant, she may not eat. Even though she is now carrying his child, she still does not eat Terumah.
"Yaldah - tochal" - once she has given birth, she may eat. Once she has borne the kohen's son, even though she was never married to him, she eats Terumah on account of the child.
"Nimtza kocho shel ben gadol mishel av" - it turns out that the power of the son is greater than that of the father:
The father, who cohabited with her without kiddushin and without nisu'in, does not entitle her to eat Terumah, whereas the son, his own offspring, does entitle her.
"Ha'eved posel mishum bi'ah ve'eino posel mishum zera" - a slave disqualifies on account of cohabitation but does not disqualify on account of offspring:
A Canaanite slave who cohabited with the daughter of a kohen: his cohabitation disqualifies her from the Terumah of her father's house, since she has become a zonah. But he does not disqualify on account of offspring: ordinarily, the daughter of a kohen who has a son from a Yisrael is disqualified from Terumah because of that offspring, but a descendant who is a slave - a son, a grandson and so on - is not considered her offspring, and therefore he does not disqualify her.
How so?
The daughter of a Yisrael who married a kohen, or the daughter of a kohen who married a Yisrael, and she bore him a son, and that son went and cohabited with a maidservant and she bore him a son - that child is a slave. The child does not follow his father's lineage but that of his mother the maidservant, and so the woman's grandson is a slave.
"Haysah em aviv bas Yisrael l'kohen - lo sochal biTerumah" - if the father's mother was the daughter of a Yisrael married to a kohen, she may not eat Terumah. Had she had offspring from the kohen she would eat Terumah, but a descendant who is a slave is not considered offspring, and therefore she does not eat.
"Bas kohen l'Yisrael - tochal biTerumah" - if she was the daughter of a kohen married to a Yisrael, she may eat Terumah. Offspring from the Yisrael would prevent her from eating, but here, even though her husband died and her son died and this grandson remained, the slave is not considered her offspring, and she returns to eating Terumah.
"Mamzer posel uma'achil" - a mamzer disqualifies and entitles:
A mamzer disqualifies through his cohabitation, and entitles when he is her offspring. It is worth noting that the Mishnah does not trouble to explain how he disqualifies, but simply establishes that if he cohabited with her she is disqualified; it spells out only how, as a descendant, he entitles her to eat Terumah.
How so?
The daughter of a Yisrael who married a kohen, or the daughter of a kohen who married a Yisrael, and she bore him a daughter, and that daughter went and married a slave or a non-Jew and bore him a son - that child is a mamzer. The child follows his mother: he is Jewish because his mother is Jewish, and according to our Mishnah the fact that his father is a slave or a non-Jew makes him a mamzer. We do not rule this way; rather, the child is not a mamzer.
"Haysah em imo bas Yisrael l'kohen - tochal biTerumah" - if the mother's mother was the daughter of a Yisrael married to a kohen, she may eat Terumah. She needs offspring from the union with the kohen in order to eat, and even though her husband died and her daughter died, this grandson, though he is a mamzer, entitles her, for after all he is the offspring of her husband the kohen.
"Bas kohen l'Yisrael - lo sochal biTerumah" - if she was the daughter of a kohen married to a Yisrael, she may not eat Terumah. The child is the offspring of the Yisrael, through whom she does not eat Terumah; and even though he is a mamzer, he is still considered offspring and disqualifies her.
In summary: In this Mishnah we learned that cohabitation without kiddushin - by rape, by seduction, or by one who is not of sound mind - neither disqualifies nor entitles, unless the one who cohabited with her is not fit to enter the congregation of Israel. We saw the power of the child: the daughter of a kohen who conceived from a Yisrael is disqualified, whereas the daughter of a Yisrael who bore a child from a kohen eats - "Nimtza kocho shel ben gadol mishel av". And we saw the two exceptions: the slave, who disqualifies on account of cohabitation but does not disqualify on account of offspring, since he does not follow his father's lineage; and the mamzer, who disqualifies through his cohabitation and entitles when he is her offspring.