Leviticus 18:11

9 You must not have sexual relations with your sister, either your father’s daughter or your mother’s daughter, whether she was born in the same home or elsewhere.

10 You must not have sexual relations with your son’s daughter or your daughter’s daughter, for that would shame your family.

You must not have sexual relations with the daughter of your father’s wife, born to your father; she is your sister.

12 You must not have sexual relations with your father’s sister; she is your father’s close relative.

13 You must not have sexual relations with your mother’s sister, for she is your mother’s close relative.

This was said to Israel at a particular time, so it is wise to read it together with the surrounding text. Do read the surrounding verses too, because the context often says more than a single verse.

Compare

BSB
You must not have sexual relations with the daughter of your father’s wife, born to your father; she is your sister.
KJV
The nakedness of thy father’s wife’s daughter, begotten of thy father, she is thy sister, thou shalt not uncover her nakedness.
WEB
“‘You shall not uncover the nakedness of your father’s wife’s daughter, conceived by your father, since she is your sister.
ASV
The nakedness of thy father`s wife`s daughter, begotten of thy father, she is thy sister, thou shalt not uncover her nakedness.
DARBY
The nakedness of thy father's wife's daughter, begotten of thy father: she is thy sister: thou shalt not uncover her nakedness.
BLB
The nakedness of the daughter of the wife of your father, begotten of your father—she [is] your sister—you shall not uncover her nakedness.
ÅB
Din stedmors datter, som også er din fars datter, skal du ikke ha omgang med; hun er din søster.
OTB
Din fars kones datters nakenhet, som er din søster, skal du ikke avdekke.
B1930
Din stedmors datter, som også er din fars datter, skal du ikke ha omgang med; hun er din søster.

Study notes (Tyndale)

Original text and word study