O passado de Chell tem que ser inferido do conteúdo do jogo, já que muito pouco é explicitado. Nós conhecemos do Portal 2 da Valve Comic " Lab Rat " que Doug Ratmann a colocou no topo da fila de testes porque o GladOS tinha anteriormente rejeitou-a como sendo inadequada para testes devido à tenacidade excessiva, mas isso nos diz pouco sobre suas origens.
Os spoilers do Portal 2 seguem:
One of the science exhibits at the "Bring your daughter to work" day is indicated as being by Chell. While everyone else seems to have made a potato clock, Chell created a mutant potato with accelerated growth. From this we can conclude (a) Chell is the daughter of an Aperture worker (b) she appears to be something of a scientific genius and (c) she has apparently aged somewhat by the time of the original Portal. (This aspect of the game is somewhat problematic - how has she had time to grow to adulthood if only woken for periodic tests? One can assume she's been in cryo for quite some time, but that doesn't seem consistent with Ratmann still being alive.)
Mais spoilers, incluindo especulação com base no conteúdo do jogo.
GladOS finally letting go of Chell at the end of Portal 2 offers some clue as to Chell's parentage. As revealed by Portal 2 the personality upon which GladOS is based is that of Cave Johnson's secretary Caroline. Although GladOS claims to have erased Caroline at the end of Portal 2, it wouldn't be the first time she has lied. The Turret Opera in particular seems to be a song expressing deep motherly affection for Chell. It is likely that Chell's mother is actually Caroline. Her father remains a matter of pure speculation, but given Cave Johnson's apparent fondness for Caroline (as exhibited in the fact he wanted her to be used as the AI template), the idea that Cave Johnson himself is Chell's father remains a strong possibility. This is possibly backed up by Chell's scientific prowess, but it's never clear whether Cave Johnson is responsible for any of the actual Science at Apperture or whether he is a non-scientist CEO.
Mais informações sobre o Chell podem ser encontradas aqui .