Did Jefferson's younger brother father a child by a Sally Hemings sister?

 Herbert Barger, founder of the Thomas Jefferson Heritage Society and an outspoken critic of the claim that Jefferson fathered two, four or even six children by his mulatto slave, Sally Hemings, is urging  everyone to read a new book that sheds light on the mores of life on  Jefferson’s  “little mountain” after sundown. The book offers convincing evidence that Jefferson’s younger brother, Randolph,  fathered a child by Sally Hemings’s  older sister, Betty Brown Hemings.   Randolph often visited Monticello and stayed very late, playing his fiddle and enjoying midnight frolics that his brother Thomas apparently ignored in his nearby splendid mansion. 

         The new book is  From Whence We Came by M. Marilynn Jefferson. She offers strong evidence that  Randolph Jefferson fathered her ancestor, Edwin Jefferson, with Betty Brown Hemings. Barger praised the book for its  “careful research.”  The current managers of Monticello claim that records show only a few visits from Randolph, who lived about twenty miles away. But Mr. Barger argues he was such a fixture on the little mountain, there was no reason to write down every visit. In Barger’s view, this reinforces the possibility that Randolph may also have had an affair with Sally. Their mother, Elizabeth Hemings, had eight children by eight different men during her years at Monticello.