User blog comment:ElizabethVictoria00Catasthrophe/Izuku is not really quirkless/@comment-26821421-20180326140832

Well, considering that by the time Deku was old enough to be entered into UA (I believe 15?), he still hadn't produced his quirk, which people normally produce from the age of four or lower, he'd have to be an extremely, extremely rare case. Rarer than the case of being quirkless, which is currently 1/5 of the popin ulation.

And while it might have been his instinct that allowed him to jump and save Ochaco, that's still not exactly proof that he had that instinct all along because he had a quirk. It's the same way that if you saw someone attacking an innocent person, even if you'd never gotten into a fight, you'd have the instinct to try and help that person. It's instinct, but it doesn't mean you've done it before.

As well, considering what the doctor said, about the missing second joint in the pinkie toe, since the doctor says it with certainty that Deku will never get a quirk (Instead of saying he has a lower chance of getting a quirk), it's likely to assume that near 100% of all cases of people still having both pinkie toe joints result in them not producing a quirk.

Also, just to note, Gran Torino never held One for All. He was just Toshinori's mentor that helped him use the power of One for All. How he did this is likely the same as how he help Deku, which was giving him seemingly menial tasks, and letting it come naturally, like Mr. Miyagi trains Daniel in the Karate Kid movie.