Originally Posted by mr. peasant
I think the point being made is that they are all exceptionally young (even within the context of their respective settings), they are all techies, they are all functioning as support to the more action-oriented members of their respective teams, they are all prodigies of their fields, and they bicker a lot.
That's quite a few points of similarity, imo.
And still, none of that was invented by NCIS. Tnhery're pretty basic archetypes.