My wife is very picky. Our first kid was very picky but eventually grew out of it and started trying new things, shes glad she did.
My youngest started off basically trying everything and for the most part liking it.. then as she got older she started liking less and less, example: she used to eat broccoli and corn as a baby, now wont touch it. But shes gone on what I first concidered a downward spiral eating less and less and limiting herself to basically only the 'crappy' stuff. She even got the point on not wanting to eat meat, which baffled all of us as we're meat/potatos folks. But shes coming back around. I chalk it up to cycles. But I also think it has alot to do with what a mother eats while shes pregnant and texture in foods is a big thing too. My youngest used to love a bean and cheese burrito, then BAM one day hated cheese. I know at one point she was eating to fast and choked on a chunk of melted cheese, I think this had something to do with it as well as the texture. I've found that certain things she doesn't like have a 'mushy' texture to them, mashed potatos is a good example. I've also learned from my parents that 'everything in moderation' won't kill someone, and that with the right 'prodding/motivation' she'll try new things. I'm pretty sure she'll come around some day just like her older sister so I'm not to worried about it.. in the meantime I've taught her that fast food is junk and we stay away from it as much as possible... now my wife.. I don't think she'll ever change but she does surprise me every once in while with trying something new.