I'll give you a real life example, that I wanted to blog about anyway, to point out why it is so irritating when someone does what I'm about to do.
Kara Brown gives examples from Not Terribly Ancient Movies (Mean Girls, the Star Trek reboot) in which the women playing mothers are way too close in age to the actors playing their putative offspring. This is meant to show how Hollywood requires women over the age of (25? 30? 35?) to exclusively play mothers, and this does not happen to men, who instead keep getting paired romantically with ever younger women. This is a true phenomenon and very annoying; the best example of the lot is Susan Sarandon playing Melissa McCarthy's grandmother.
Now here's the annoying counter example. Sean Connery is about 12 years older than Harrison Ford, if the wikipedia entries are to be believed. And Sean Connery played Jones pere (not sure how to do accents on this keyboard -- pretend I put one in and I'll try to fix it later) in Indiana Jones and the Last Crusade.
The reason it is so annoying is that it is, actually, way easier to find examples like the ones Kara Brown brings up, than the one I bring up. I like the Connery/Ford example _because_ it is so amazingly unusual, and I feel like the world would be better if we had more middle aged men who were really too close in age to _be_ father-and-son appearing as father-and-son so they could both be Hot Dad Types at the same time (more bang for the movie goer buck, was how I put it back in 1989). The only current example I can think of occurred with the new Q in Sky Fall when Bond/Craig (46) makes this huge deal out of how young Q/Whishlaw (32) is. Not actual father and son, but a related phenomenon. Similarly, I was pleased in the same movie at the 30+ year age gap between Albert Finney and Craig, further evidence that Brown is right, and my counter examples are Not Representative.
It is annoying when a Smart Person Who Knows Tons goes to enormous effort to find the one counterexample in existence. The Smart Person Who Knows Tons could instead think of this rare counterexample, go, hey, I can only think of _one_ counterexample, and then go, "Gosh, I think you're right. I can think of a lot more cases that support what you are saying than go the other way. You are onto something." And Know It All would lose a little of its sting, if our collective experience of Know It All types were friendly like that.