Some of the timeline of Thomas Jefferson is specious. There is no evidence that Thomas Jefferson fathered any of Sally Hemings' children. The DNA test that was done only showed that a Jefferson male fathered Eston Hemings.
The descendants of Eston were told Eston was fathered by a Jefferson "Uncle." There were many male Jeffersons who lived near Monticello. The most likely person to have fathered Eston was Randolph Jefferson, who had a reputation for spending lots of time with the Jefferson's slaves, playing music and dancing long into the night. Jefferson himself denied all of the accusations, saying that the only transgression he was guilty of was courting a married woman before he was married. Thomas Jefferson's worst enemies in his own day and in the present day, including historian Forrest McDonald, have said there is no basis for the claims.