Could Jefferson Davis really be Thomas Jefferson?
No. There is no way that Thomas Jefferson and Jefferson Davis were the same person. The reasons are thusly: Jefferson was born April, 3, 1743 and he died July 4, 1826. Davis was alive during the Civil War.
YES A doctor castrated Thomas Lincoln when he was ten years old, and Thomas could not have children. Many men have been named as the father of Abraham Lincoln; Thomas Lincoln is one and he was not the father of Abraham Lincoln. Abraham Lincoln's father was Samuel Davis not Thomas Lincoln! Samuel Davis also had a son named Jefferson Davis. Source: Lincoln, Davis, and Booth: Family Secrets