In S1 (2007) Blair turned 17. In S2 (2008) she turned 18, so yeah it'd be 1991 :) They're turning 18 this season (2009)...

It's either 1991 ot 1990. At least I think so.

Blair was born in 1990 (like Natasha said, since she turned 18 in 2008). But I think the others were born in 1991. At least Chuck was, since he wasn't 18 yet during the whole Bart's death/Jack/Bass Industries arc.

Wow, complicated stuff. :P

They're the generation 1990/1991 :D
Not all of them are born in the same year...

Yeah in US, I guess not all of them would be born in the same year. End of 1990 - 3/4 of 1991(I guess)

or 1991, mine is 1991 as well ands i am 18, how old are they?

They aren't all born in 1991. Blair's birthday is in November, while Chuck's is in May, and so they were both 18 by the end of May 2009...at least according to the show.

i agree with waldorf

I reckon 1990-91 school year.

i agree with waldorf.
because some of them are born in 1990 and some of them are born in 1991 but i deffinetly hope that chuck is the same age as blair or older because i beleive in relationships the guy should never be younger then the women but thats just what i think. there birthdays are realy complicated