Females inbloodlinefamilies have sex with multiple males 10 x their age. Sometimes the purpose is ritual magic, others reproduction.
Robert Wood Johnson had sex with his daughter, and then with her daughter and then with her daughter he may have got a fourth gen on that - it's unclear. The Polish maid he eventually married probably prevented his hat trick +
https://www.dailymail.co.uk/news/article-2303961/Maid-married-Johnson-Johnson-heir-won-300-million-estate-notorious-court-battle-children-dies-aged-76.html