Build a Family Tree (Men Only) by Marti Louw The Y chromosome is the keeper of family history on the male side. Written in the letters of DNA, it carries a record of a man's paternal ancestors.

Sam Hassan, an American-born Lebanese Muslim, and Toufic Hajjar, a Lebanese-born Christian, have known each other since the 1940s, when they shared friends, language and culture in Quincy Point, a ...