(Devarim 23:2) "A petzua dakah and a kruth shafchah shall not come into the congregation of the L-rd.": What is a "petzua dakah"? One whose testicles have been injured ("niftzeu") — even one of them. This tells me only of the whole of it. Whence do I derive (the same for) even part of it? From dakah (lit., "crushed," but not entirely).

"and a kruth shafchah": wherever the organ is cut.

R. Yishmael the son of R. Yochanan b. Beroka said: I heard in Kerem Beyavneh that a man who has only one (testicle) is a saris chamah (a eunuch from the time of seeing the sun. i.e., one born without visible testicles. [This has various halachic implications.]) What is the difference between a petzua dakah and a kruth shafchah? A petzuah dakah can recover (from the injury); a kruth shafchah cannot. This is one of the "halachoth" of doctors.

"into the congregation of the L-rd": the congregation of Cohanim, the congregation of Levites, the congregation of Israelites, and the congregation of proselytes.

The sages say: There are only three. (He omits the congregation of proselytes.)