One of the conceits of Wai Siu Bo's character was that not he, his mother, nor anyone else in the world knew whom his father was. "Wai" was not his proper surname...just the one he took from his mother because nobody had any idea whom his father could have been. Why don't we have some fun speculating?
Is it possible that Wai Siu Bo could be the descendant of an earlier Jin Yong hero? Let's consider the possibilities:
1. Kiu Fung - Probably not. Kiu Fung is not known to have sired any children prior to his death in DGSD. Ah Chu was the only female lover he ever had, and they didn't make any babies before she died at his hands.
2. Hui Juk - Not a very high probability, but possible.
3. Deun Yu - I have suspicions about Deun Yu being an ancestor of Wai Siu Bo's because of their predilection towards multiple beautiful young women and their incredible lifesaving good fortune. Both of them are highly sensual individuals who appreciated their creature comforts. Both were also known for their silver tongues.
4. Gwok Jing - Not likely. Gwok Jing's lineage ended with his children, and it's not said that Gwok Fu, Gwok Seung, or Gwok Por Lo ever had any offspring. Moreover, Wai Siu Bo has nothing in common with Gwok Jing.
5. Yeung Gor - Remotely possible, but also not especially likely. I don't know if Wai Siu Bo was supposed to have been handsome, but it's doubtful he had any Yeung Gor or Little Dragon Girl DNA in him.
6. Cheung Mo Gei - I have strong suspicions about this one. Again, as was the case with Deun Yu, we've got a man who has interest in several beautiful young women, and a predilection of accidentally becoming a leader in an anti-foreign invader wulin sect/society.
7. Ling Wu Chung: Both are easygoing, but I don't see any obvious possible connection between the two.
8. Yeun Sing Chi: "I am your father?" Yeun *was* around when Wai Siu Bo's mother was a young woman. You think maybe....? Nah....