20The big age difference
The actors playing Mark and Lexie have only a nine-year age difference between them; however, the characters have a very marginal sixteen-year age gap. Mark Sloan was born in 1968 while Lexie Grey arrived in the world in 1984.
The difference in ages between the two came up quite a lot
on the show, which was one of the reasons why Mark didn’t consider Lexie to be one of notice earlier on. But it wouldn’t be long before Mark did turn his attention toward Little Grey and we all know how the journey went.