As a kid, I had never tasted custard until I was 5 years old. I think it was vanilla flavored custard that I tasted first, and when I did, it tasted like one of those growth syrup that are given to kids! Yucky. I almost threw up. The reason, I had tasted vanilla flavored syrup before I tasted custard. So, my mind had made up its mind that the syrup is yucky and I was forced to drink it for its good qualities. Later on in life, when I tasted the REAL thing, my brain registered it as yucky.
So, I concluded that the order, in which you expose your kids to things, is very important in setting the right perceptions. I was never exposed to fish as a kid, and when I smelt it first, it felt horrible. My brain equated that particular smell to cow dung (that is what fresh cow dung smells like, for those of you farm environment deprived), which was already programmed into the yucky category.
Whenever our daughter's daycare is serving fish, I feel uncomfortable walking in. Since, the smell makes me uncomfortable, I used to think that she also felt the same. Actually, she did not. The very first time she registered the smell, she saw her classmates eating the source with joy. So, her brain programmed the smell as a good tasting snack smell. This is how the culture barrier is broken!
Sometimes, grownups acquire tastes to certain things even though it is repulsive at first. These are acquired tastes. Children can also acquire tastes as long as they are exposed to positive thoughts.