https://en.wikipedia.org/wiki/The_President%27s_Daughter_(Britton_book)The President's Daughter is a 1927 book by Nan Britton describing her extramarital relationship with Warren G. Harding, the President of the United States, during which they conceived a child. The book is considered the first popular bestselling kiss-and-tell American political autobiography published in the United States and caused a sensation when it was released. In 2015, DNA testing proved the book's central claim that Harding was the father of Britton's daughter Elizabeth Ann Blaesing.
https://archive.org/details/presidentsdaught00brit/