As far as I can tell, my great-grandmother, who emigrated from Prussia near the turn of the century, brought the cruelty of incest from her home country to Grand Rapids, Michigan.
I can only imagine who sexually assaulted great-grandmother. I wonder how far back, how many generations passed on incest and sexual molestation to their own children and grandchildren.
Before I started remembering my grandmother sexually abusing me, I had never heard of grandmother to granddaughter incest. I even naively tried looking it up online but all I found were pornography sites. Really?
In looking up incest statistics, I know that stepfather-stepdaughter incest is most common followed by biological father-daughter incest.
However, the underreported brother-sister incest may be the most common. I'll do some more research on these statistics that are obscure and best guesses.