https://www.thejc.com/judaism/features/was-the-chief-rabbi-right-to-speak-on-gay-marriage-1.34487
...It is true that the 613 commandments of the Torah are binding only on Jews. But according to Orthodox tradition, there are also universal standards of morality to which the righteous of all nations should subscribe. The rabbis termed these the seven Noahide laws, which variously proscribe murder, blasphemy, sexual immorality etc...
... When it comes to forbidden sexual relationships, some rabbis count all those listed in Leviticus 18, the arayot, which include incest, adultery, bestiality and male homosexual intercourse...
... “There are 30 commandments the sons of Noah took on themselves but they observe three of them” (the 30 are presumably specific commandments that fall under the more general heading of the seven).
One of the three observed by non-Jews is that “they do not draw up a ketubah [marriage contract] for males” (Chullin 92a); in other words, they do not legitimise same-sex unions...
I didn’t know it was in the Noahide laws (Noachide?).