The Sontaran Stratagem (Geniuses)
If I were to tell a human that their child was a teenage genius, they would be extremely happy. Proud that their child might be able to improve the world, and do something great.
I completely disagree.
I don't think I've ever met a human who reached "genius" status while a teenager who wasn't corrupted at at least one point in their life. Take Rattigan for example. He's incredibly smart, he's done great for the world, but nobody ever contradicts him. Maybe that's why he agreed to help the Sontarans.
Screw humans, I don't think I've ever met a non-corrupted genius EVER. Well, maybe my Doctor. But I'm not so sure…