In ep #564, Joe is visiting Tom's grave, and the headstone reads:Thomas Jennings 1944 - 1968In ep #676 which taped/aired in January, 1969, Chris tells Barnabas that his first transformation occurred right after his 21st birthday, 7 years before.These events indicate that Chris is older than Tom by a few years.
(I hope I used the spoiler button correctly)
[spoiler]the "surprise" goes here[/spoiler]not a spoiler
[spoiler] But Magda, when she laid the curse on Quentin, cursed ALL his male descendants as well, and that should have included Tom. She didn't say, 'all of his oldest male descendants.' [/spoiler]