Question (R. Elazar citing R. Chanina): What is the source to say that just like a Jew, a gentile is prohibited from having forbidden relationships?

Answer: The pasuk states (Bereishis 2, 24), "...and he shall cling to his wife'' - but not to another's wife, nor to a male, nor to an animal.

R. Shmuel/ R. Abahu/ R. Elazar citing R. Chanina: A gentile who had relations with his wife in the irregular way (i.e. from behind) incurs the death penalty. What is the source for this? (ibid), "...And he shall cling to his wife and they shall become one flesh'' - (they may only have relations) in the place where they could create one flesh, meaning by reproducing.

Question (R. Yosi): Would a gentile be liable for committing only the first stage of relations with a male or with an animal?

Answer: All forbidden relations, including relations with a male and with an animal, are learned from the case of Nidah. (He would therefore be liable, like the case of relations with a Nidah.)

Question: However, a gentile is not forbidden from having relations with a Nidah, so this cannot be a source. So what is the source of this prohibition for a gentile?

Answer (R. Mana): We can learn it from the earlier pasuk. Just as we learn "...and he shall cling to his wife'' - but not to another's wife, even without completing the act; this also applies to relations with a male or with an animal.