>I won't quibble about the common Jewish assumption that Sarah was
> biologically Abraham's cousin, (See Josephus, Antiquities of the Jews, Book
>1, vii, 5) This apparently came about because Sarai was Haran's daughter.
>Haran was Terah's son. When he died, Terah adopted them, making Sarah an
>adopted sister but biologically a neice.
Foundation,Fall and Flood
http://members.gnn.com/GRMorton/dmd.htm