Aired: 1990 
Questionable Dad: David Stewart (Stephen Collins) 
Why It Doesn’t Count: David and Sarah are single parents who meet during a cooking class and decide to "work out" their relationship. David is a single dad. What’s the problem? We NEVER SEE his kids — they’re AWAY at college. This violates Rule One of the Single TV Dad Rules: The Single Dad must be seen in a parental role, caring for his "children" without their biological mother or stepmom. Dad must have an obvious participation in providing for his children’s well-being.
The implicit thought here is that we, as viewers, must actually SEE these kids on screen at least once. This never happened during the brief history of that show.