Psh...Age, Gender, the fact that Blaine's basically Genny's height, even though he's a year older *and* a guy...These are irrelevant facts. THEY'RE TWINS, DAMN IT! (see that emotion? pretty good, huh?)
Genny's totally going to make him bring that angst out and get it over with, btw. Either that, or she's going to be moping about Jeff leaving and decide that they need to spend a day doing nothing but watching The Notebook and crying (chocolate ice cream is a given).