Jefferson made 22 visits to Monticello during the relevant conception years, yet no conceptions occurred during 17 of those visits. When suggesting an ongoing relationship, is important to note that Jefferson did not bring Sally Hemings with other slaves to Washington DC where he spent 8 years as President 1801-1809. After his presidency, Jefferson returned to Monticello in 1809 and Sally Hemings stopped having children....
What is more likely, and a simpler explanation, is that Jefferson’s male relatives would visit Monticello and have much more freedom to “sneak off”, while all attention and responsibility was on Thomas Jefferson as he entertained guests as host. Among others, a highly likely candidate for such behavior was Jefferson’s brother Randolph Jefferson, who was 12-years younger, lived a mere 20 miles south, and carried the same y-DNA as his brother Thomas.
https://www.tjheritage.org/uncle-randolph-jefferson-thomas-jeffersons-younger-brother
