Acharei Mot-Kedoshim, 5777/2017 thoughts

As I said here:

• Parshat Acharei Mot: In Leviticus chapter 18, verses 6-21, the enumeration of anti-incest laws, there's no mention whatsoever of the most obvious form of incest--there's no directly-stated prohibition against a father having sex with his daughter. Sure, it's common sense and common decency to avoid such a heinous act, but so are all the other enumerated "forbidden relationships."

It occurred to me that this omission is probably "covered" by one of Rabbi Yishmael's rules of interpretation:  Mi-binyan av mi-katuv echad, u-mi-binyan av mi-shnei k'tuvim (A general principle derived from one text or two related texts).    In this case, the general principle is "None of you shall approach anyone who is near of kin to him, to uncover their nakedness (Leviticus 18:6)."  This general principle would certainly apply to one's own child.

But an Israeli-American of our acquaintance told us that the Israeli rabbinate still permits the marriage of an uncle and his niece.  How, exactly, can that be mutar (permissible), given the fact that having sex with one's niece is a clear-cut case of "uncovering one's brother's nakedness"?