What is the difference between a 'Petzu'a Daka' and a 'K'rus Shafchah'?
Rashi: 'Petzu'a Daka' is a man with crushed testicles 1 and a 'K'rus Shafchah' is one whose organ has been partially 2 severed 3 (neither of whom is able to father children). 4
Yevamos, 49a: 'Petzu'a Daka' is where a man's testicles are crushed - even one of them, and even if it is holed, squashed or ir there is a bit missing.
Yevamos, 75b #1: "Patzu'a Daka" is confined to bi'Yedei Adam - as implied by the word "Petzu'a" (and not 'Petzia'); 5 Petzi'a Daka bi'Yedei Shamayim is therefore Kasher. 6
Yevamos, 75b #2: Both "Patzu'a" (a wound) and "Daka" (crushed) refers to all cases. Consequently, the prohibition applies to where either the Gid (the organ), the testicles or the sinews of the testicles are wounded or crushed. And the same applies to where any of the three have been cut off. 7
Sifra: "Petzu'a Daka" implies even if only part of the testicles are crushed.
See Sifsei Chachamim.
See Torah Temimah, 13.
However, if even a hairsbreadth remains below the crown, he is Kasher. See Torah Temimah, note 13.
Rashi: The latter, because the seed will no longer shoot like an arrow.
See Torah Temimah, citing the same Gemara, which learns it via a Gezeirah Shavah "bi'Kehal Hashem" "bi'Kehal Hashem" from Mamzer - in Pasuk 3.
See Torah Temimah, note 6.
See Torah Temimah, note 11 who elaborates.
How do we know that "K'rus Shafchah" refers to the Gid (the male organ) and not to the lips or the nose?
Yevamos, 75b: Because the term 'K'rus Shafchah' implies that the blood only pours when it is cut off; otherwise it flows - as opposed to the nose and the lips, which pours at all times. 1
See Torah Temimah, note 8.
How do we know that "Petzu'a Daka" refers to the testicles and not to some other part of the body?
Yevamos, 75b: We learn that it is not the head from the fact that the Torah compares it to "K'rus Shafchah". 1
See Torah Temimah, note 9.
What does the Torah mean when it writes "Lo Yavo bi'Kehal Hashem"?
Rashi (in Pasuk 3) 1 and Targum Yonasan: It means that he is forbidden to marry a (Kasher) Yisre'elis 2 (though he is permitted to marry a Giyores or a Shifchah who has been set-free - Yevamos, 76a). 3
See Sifsei Chachamim. Oznayim la'Torah: Rashi did not write ithere, b ecause, seeing as the Petzu'a Daka did nothing wrong, it is obvious that that is what the Pasuk means, as opposed to a Mamzer whose parents sinned be'Chayvei Kareis and who is therefoe like to be like them and an Amoni and a Mo'avi, who also have it in their blood to be evil, Rashi needs to mention it, since we might otherwise have thought that "Lo Yavo ... bi'Kehal Hashem" means to distance him from every Davar she'bi'Kedushah.
He is permitted however, to marry a P'sul Kahal like himself- such as those listed in the current Pesukim.
