When my late husband and I started doing genealogy, we found many coincidences between his ancestors and my first husband's ancestors who were of German extraction. Both families had ancestors who came to Texas around the same time, lived in the same communities, attended the same church, and moved farther north to the same county at the same time. Both my husbands' fathers were carpenters at the same army base and at the same time. And a few years ago, first DH's cousin lived down the road from my 2nd DH's sister. But, to our knowledge, neither family knew the other.