User blog comment:Heinz84/Could Dr. Doofenshmirtz be Phineas and Candace's Biological Father?/@comment-1647442-20100721161013

Plus, it doesn't make sense to me that he would have Vanessa, leave Charlene for Linda, have Candace and Phineas, then go back to Charlene (Well, technically not back, but keep in touch with her and not Linda)