in the episode Dreamscape, rose lures the chimera into her deep subconsious to her earliest memory, her birth. she learns that she is 1 of 2 twins, and was taken from her parents because of the birthmark.
but in homecomming, after jake makes the wish to save her life she gets in a car with her paretns... but wheres her twin?
and in hong kong longs... her twin is yet again absent.
either theres a serious plot hole, or the writers totally forgot about rose's twin.