Syaffolee has a post about picky eaters.
As a veteran picky eater, brother of one, husband of one, and father of two, I have some random thoughts to share on the issue. (Btw, I agree with Sya's basic assertions.)
As as kid, I was probably the worst kind of picky eater to be. I hated hated hated hot dogs and pizza. Guess what moms serve every single freakin time little boys ever congregate?
Even weirder, I loved things like spinach, chow mien, all forms of meat, and only one vegetable was and is on my "no fly" list.
My mom was (is) a hell of a cook, and I suspect the way she made things spoiled me to the way other moms made them. I recall being served white (potato) pancakes with boysenberry syrup at a friend's house, and having been told by my buddy we were getting pancakes, when they hit the table, I looked up at his mom and asked in all sincerity: "What are these?" She was one of the most accepting and kind moms of our group, but I still recall her being pissed off at me for about a week.
Around late adolescence I suddenly got over most of my pickyness, which I think is common for most of us. I think it was the reality of the school cafeteria that made me have to adapt or starve, plus the voracious appetite of that age. My teenage daughter has gone from eating tiny portions at dinner to going back for a big helping of seconds.
I still can't stand brussels sprouts. To me, they are like little bitter little cabbages whose center has rotted to a mushy yellow. How in the world can anyone think they're good?
My wife still won't eat most vegetables and fruit. You wouldn't have to involve your toes if you were to use your available digits to count the few veggies and fruits she'll eat. She claims to have never been a big veggie fan, but apparently a disastrous attempt to lose weight once using a fruit diet ruined her already tenuous acceptance of that food group.
To make life additionally difficult for my parents, my brother was a picky eater whose list of things he liked were nearly a completely separate yin to my yang. He hated meat and veggies, mostly liking pasta, potatoes, and bread - things I tolerated, but wasn't a fan of.
My father once forced my brother to eat something he'd refused to, and my brother promptly barfed at the table. That was the last time either of us were forced to eat anything. We were still cajoled, but never forced again.
At one of my brother's birthday parties when he was about 10 years old, mom had used a marshmallow frosting on the cake. My brother's best friend couldn't stand marshmallow, but was raised to never refuse food given to him at someone else's house. He forced it down, tried to play, but finally had to step around the corner of the house and puke, where mom found him in a miserable little pile. He was so nauseous from the frosting that he couldn't stop puking, and his mom had to come get him.
My own kids both started out eating about everything we gave them. The only early exceptions were some forms of baby food. Eventually both my wife and I tried the concoction that made the baby gag, and agreed it was pretty heinous. There must be a group of jarred baby food cooks who don't think babies have tastebuds. Nearly every concoction that's a combination of meat and veggie tastes like a little spoonful of distilled hell. Gerber even proudly announces the very reason this is true on a little blinking banner as you try to surf their horrifically designed website: "Did you know? GERBER purees contain no added refined sugar, salt, or starch." We started to add sugar and salt to the ones that could be rescued with the addition thereof, and never bought again those that couldn't, like the meat and veggie abominations.
We even noted that after the baby (we only did it to the first one) had suffered through a meat/veg jar, she wouldn't eat well for a couple days, as though it had triggered the taste aversion that occurs after you've puked up a particular food. Only once we clued in and gave her things that tasted good to us did that weirdness go away.
...Until about the age of four. Both kids at that age started forming preferences that were/are seemingly random. The eldest hates potato soup, though the youngest gorges on it. The youngest has decided that sub sandwhiches are little slices of pure evil, while the eldest constantly asks to go to Subway.
Neither really likes breakfast cereal, which was my staple as a kid. I probably consumed enough Cap'n Crunch to create a barge out of the boxes. I even have JFK-assassination-like sense memory of the first time I ate the stuff. I was so excited to taste it, my mom let me have a bowl after dinner. I still remember where I sat in the kitchen when I ate it, what it looked like (70s brownish tile), and so on. I even remember that odd thing it does to your mouth, leaving the roof of your mouth feeling slightly shredded.
I've noted that as my eldest stays over at friends houses, and goes on daytrips with them and their families, that her palate is expanding. As a parent, it's a bit annoying that they won't try new things when you suggest it, but when forced to try something to be a polite guest, they suddenly announce (though as casually as possible hoping it won't cause parental feather-ruffling) that, oh, yeah, they like peas now. But you takes your gains where you can gets them.
On the flip-side, some of my eldest's friends do the same thing, and - even more gratifying - will only eat my version of a dish that they won't touch at home. That makes up for my own kid's culinary betrayals.
As the article Sya references points out, the one apparently universal food that everyone likes is fried chicken. Go fig.