The 361st prohibition is that we are forbidden from damaging the reproductive organs of any male, including all species of animals, as well as humans.

The source of this commandment is G‑d's statement1 which follows mention of [animals whose reproductive organs were] crushed by hand or by instrument, pulled loose, or severed — "in your land you may not do this."

[Our Sages2 gave] the explanation of this verse: "among you [i.e., by Jews] it may not be done."

One who transgresses this prohibition — i.e., who castrates one from any species — receives lashes.

In the chapter Shemonah Sheratzim,3 our Sages said, "What is the source for the prohibition of castrating a man? The verse, 'in your land you may not do this' — i.e., among you.4 Even the second one to damage a reproductive organ5 transgresses this prohibition, as Rabbi Chiya bar Abun said in the name of Rabbi Yochanan: 'everyone agrees that the second one to make [a meal offering] into chometz [also] transgresses, since it is written,6 "do not bake it chometz," and7 "do not make it chometz." The second one to damage a reproductive organ transgresses since it is written, "crushed by hand or by instrument..." If one transgresses for crushing by hand, it is obvious that one transgresses for crushing with an instrument! But this comes to include even one who crushes with an instrument after they were already crushed by hand — that he too transgresses.' "

The details of this mitzvah are explained in a number of passages in Shabbos and Yevamos.