Heinz Doofenshmirtz was most assumed in fanfiction to be Phineas and Candace's dad. It is unknown when and where this was first brought up, however on August 9th, 2011, Dan Povenmire confirmed that Dr. Doofenshmirtz is not Phineas's real father during the NY TimeTalks.
- Similarities between Heinz and Phineas:
- Triangle heads
- Hair sprouts
- Mechanical ability
- Behavior (especially during "Hail Doofania!")
- Same Hair Style
- Similarities between Heinz and Candace:
- Lactose intolerace
- Pointy head
- Large Neck
- Confirmed by Dan Povenmire that Dr. Doofenshmirtz is not Phineas's real father during the NY TimeTalks.
- Heinz's bad date with Linda, causing him to never meet her again ("What Do It Do?")
- In "A Real Boy", he does not (or is not aware that he has) have a son. "I would like a boy, in /addition/".