Paul Jones is the biological father of Sean Tully, whose birth was the result of a fling with Maureen Tully.
For most of Sean's life, his mother lied and allowed him to believe that her husband, Brian Tully was his father. In 2006, the truth was revealed to Sean by Brian; who wanted to explain that his reasons for not having contact with Sean were more complicated than Sean's belief that his apparent father did not accept his sexuality. Sean was told that his true father didn't even know his son existed.