John Krasinski -- Good Genes or Good Docs?!

Have John Krasinski's looks over the years propelled him to the "Sexiest Man Alive?!"

Here is a 26-year-old version of a smirking paper salesman on "The Office" back in 2005 (left). This was the year he started playing Jim Halpert on the hit NBC sitcom ... hands down his breakout role!

And, nearly two decades later, Krasinski pursed his lips and showed a scruffier version of himself for George Clooney's charity event at the New York Public Library (right).

The news broke earlier this week ... John was given the title of Sexiest Man Alive, but the real question here is: