Cell, (or Seru) was a creation of Dr. Gero, created from the cells/DNA of all strongest warriers at the time, which included, Goku (ofcourse), Vegeta, Piccolo, Tien, Krillin, Frieza, and King Cold. With this DNA, Dr. Gero set out to build the Perfect Android. Perfect, in that unlike his previous creations, this one would not be dependant on gears or computer chips.... He was created to be purely Bio-mechanical. The good doctor took special care in his design, making him seemingly invinsible, giving him things that his other androids hadn't even DREAMED of. And ofcourse, with the powers of all the strongest warriers, it's no wonder how strong his creation would become. The regenerative properties of Piccolo. The ability to grow stronger after every battle from the Saiyans. The ability to survive ANYWHERE from Frieza. These were some of the key techniques that made Cell truly unique. Gero incubated the Embryo that would one day be known as Cell in a giant liquidated tank which imitated a womb. Everyday, he'd keep close watch over Cell, and even lost sleep getting him prepared.

One night while Gero was working in his lab on Cell, (or Cell's embryo) Everyone's favorite androids, #17 and #18, (or as I like to call them, the Dream Team) entered the room, undoubtedly to taunt him from what I could gather. Either way they ended up killing Gero that night, and then left the lab for good. Before they left, they destroyed the ENTIRE lab. 'Bad memories', #17 had said. Fortunately, for all of us obsessive Cell fans, Cell's tank survived, and years later he finally matured enough to emerge from it. But all that met him in his first few moments of life were rubble. Yep. The entire lab was GONE. BUT..thanks to Dr. Gero and his computer, (which had kept a pre-recording of his voice in the tank while Cell grew) he knew exactly what was expected of him. He IMMEDIATLY set off to gather the bio-extract from what little humans were left. (The Dream Team Duo had went on a murderous killing spree, leaving very few lifeforms) Unfortunately, what he needed most had been destroyed. Androids 17 and 18 had already been killed in this future timeline, Trunks.

Sooo....

Having NO other choice, (obviously) Imperfect Cell was FORCED to kill Trunks and snatch his time machine. (ok, ok...maybe he didn't HAVE to kill him) And THEN he made the ultimate sacrafice; He regressed back to his larval state in order to fit into the time machine. Yes, yes. If you haven't noticed by now, Cell is a very VAIN person. And with every setback he encountered, he was just that many steps away from becoming 'Perfect', so you can imagine how he must have felt.

Cell traveled back in time, to a period when the Androids still DID exist. (Which is also the present DBZ timeline we know and love) Once there, he burrowed deep underground, and for four years, he waited, gathering nutrients and strength from the soil in which he lay. And well, after those 4 years, the being called Cell emerged, in his exoskeloten shell. He shed the shell and became his old self, setting out to absorb human bio-extract to re-gain his strength.

And that's the origin of Cell. Even though Cell was defeated by Gohan, I still think that he was Perfect. His very existance is a mere accomplishment. I mean, he was born by artificial means, he had the cells of over five people running through his veins...PLUS he was a BIO-MECHANICAL ANDROID. That in itself should merit for something. So even though Cell wasn't Perfect in quite the way he wanted to be...he was closer to perfection than even he must have realized.