NET
1 It is actually reported that sexual immorality exists among you, the kind of immorality that is not permitted even among the Gentiles, so that someone is cohabiting with his father’s wife.
Darby
1 It is universally reported [that there is] fornication among you, and such fornication as [is] not even among the nations, so that one should have his father's wife.
KJV
1 It is reported commonly [that there is] fornication among you, and such fornication as is not so much as named among the Gentiles, that one should have his father's wife.