Y-DNA testing offers at least two benefits to genealogists that autosomal DNA does not. We all know the limitation: only men have Y-DNA and it only applies to the direct paternal line, i.e. the father’s father’s father, etc. And we know the main benefit of Y-DNA: it is passed down without recombining, which means we may match distant cousins where the common ancestor is 8 or more generations back—farther in the past than automsomal DNA can generally be relied upon. We don’t hear as much about the second benefit of Y-DNA testing, but it was key for my Hammond conundrum.