Did they even consider the fact that identical cousins are biologically impossible?

Even less explainable is why the theme song to this show gets stuck in my head on a regular basis when I haven't seen it in at least 15 years.

I use to watch this on Nick and Nite. Now they show shows from the 80s on NIck and Night which confuses me since I was around when they aired the first time, unlike with shows from the 1960s. I wish they still aired shows like Laugh In.

I also used to watch this on Nick at Nite in the 80's.