An article in The ASJA Monthly claimed that journalist Ruth Gruber, now 91, had at the age of 20 been the youngest person ever to receive a Ph.D. (Well, this page says Gruber got her Ph.D. at 19, but I’m more inclined to believe an article that was a direct interview with the woman.)
Googling around, I found that Stephen Wolfram, the creator of Mathematica among other geniusical things, also received his Ph.D. by the age of 20. So did software developer Adrian Scott. So did Hugh Latimer Dryden way back in 1919, before Gruber.
Are they still the record holders or are there any actual teenage hotshots that have taken the prize?
Or were there any even before Gruber? (And, yes, I know that standards for doctorates were different when you go truly far back into history. Let’s keep it to the modern definition of Ph.D., which would be roughly from the late 19th C. on.)