Nina mentions in passing toward the end of the episode that she was 14 when Erlene was born. That's the actual age difference (14 years, and some months) between actresses Wendie Malick and Brooke Shields.
NBC throw an gimmick in which viewers can go online and vote for how they want the episode to end. The winner, the scenario with the most interactive votes, will be one of three endings: There's a) Finch makes a move for Nina's sister Erlene; b) Erlene picks up Finch; or c) "things get weird," also described by the network as "the ending they don't want you to see."