Leviticus 18:12

Thou shalt not uncover the nakedness of thy father’s sister: she is thy father’s near kinswoman.

The prohibition bars sexual intercourse with close blood relatives, with a father's sister named as one specific example of uncovering nakedness. It extends beyond the physical act to forbid sexual familiarity between men and women that erodes the protective boundaries God established to safeguard the moral purity of His people. Such behavior is not merely improper but constitutes both a legal crime and a moral sin. Its effects are especially destructive for youth, capable of ruining both their character and their physical well-being.