User blog comment:Kuzlalala/Lala's Long but Orderly Put Theory about Phineas and Candace's Biological Father/@comment-3070554-20120114152649

I think Phineas and Candace's biological father may be dead. The father was never mentioned, maybe this is because his death was such a suffering for the family that they decided to never talk about him again. If you pay attention, not even Linda ever mentioned him as an ex and, if he were alive, it would be more likely that he would like to see his kids, as Doof does: even being divorced, he's still seeing Vanessa all the time.