Secondly, the Lord prohibits sexual relationships between those who are related by blood but belong to the extended family. This includes grandchildren (Leviticus 18:10) and aunts (Leviticus 18:12–13). Wenham calls this, second-degree consanguinity.
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10 Tu ne découvriras point la nudité de la fille de ton fils ou de la fille de ta fille. Car c'est ta nudité.