Melanie was born under care of the Washington state government. She lives a pampered life for one reason - she is a performer. And not just any performer, mind you, she sings. She can also do comedy, and dancing, and pretty much all else.
She was born to do this. Literally. As a part of a program searching to better the human entertainment industry, she was born and trained from the youngest age they could possibly muster.
And it would've been that way for the rest of her brainwashed life, until the resistance broke through.