Or, more simply, affairs, unwed couples, incidences of rape that were a dark stain in the victim’s life, etc.

A friend of mine loves to think about heritage and genealogy and when I brought up genetic testing and “wouldn’t it be neat to find out if someone in your lineage wasn’t actually in it?” they were quick to point out that they’re not interested in that because it doesn’t matter and her parents are her parents (and her great great grandparents are her great great grandparents).

Discovering infidelity and/or abuse in your family tree 2-3 generations back often (but never ever always) does little but harm to one’s own genealogical journey.