I have opted to take the words of the one witness who lived through the times until such time as someone comes up with documented proof.Dennis F Hanks never wavered in stating that there were 4 sisters, Elizabeth, Mary "Polly", Lucey, and Nancy.
John Hanks, son of William Hanks and Elizabeth Hall, also stated that Nancy Lincoln nee Hanks was the daughter of Lucey Hanks.
The Lucey that married Henry Sparrow in KY was a spinster and had been charged with fornication just prior to her marriage.If she had Nancy out of wedlock, and also another daughter, then that could explain why she was not listed in her father's will.
Dennis was said to be an embellisher of stories, but he never made any outrageous claims about Abe's mother.He alone lived closer to Abe and family than any other person who spoke out to Herndon.Dennis told that he was a baseborn child but refused to allow folks to believe that Nancy Hanks Lincoln was baseborn.It is even possible that Henry Sparrow who married Lucey was the father of her illegitmate offspring and finally decided to make things legal after the court got involved. [New theory on Nancy's parentage].
My family tradition stated that my line and Abe's line came from sisters when it was passed down from Dennis to daughter Harriett, Abe's favorite stepniece/cousin, to Harriett's children on to my ggmother and in my ggmother's written words to me.I was told more than 4 decades ago that one of my gmother's was sister to Abe Lincoln's mother's mother.
My ggggggmother was Nancy Hanks who married Levi Hall, sister of Lucey Hanks who was the mother of Nancy Hanks that married Thomas Lincoln.I am the gggggson of Dennis Hanks.