“While the tests were professionally done by distinguished experts, they were never designed to prove, and in fact could not have proven, that Thomas Jefferson was the father of any of Sally Hemings’ children.”
The Jefferson-Hemings Controversy addresses the DNA evidence in some detail, noting that the tests “did no more than establish that Eston Hemings’ father was almost certainly a Jefferson.”
More than two dozen Jefferson men, including Thomas, could have been the father.
By then, though, Thomas Jefferson was 64-years-old — scarcely a leading paternity candidate...
Evidently Thomas' younger brother Randolph was known to carouse with their slaves-- making him a somewhat more likely candidate.