It's a hard one. We have the ability to offer SOOOOO many varieties of foodstuffs, that sometimes I think we worry when despite our children having a reasonably varied diet, and reasonably healthy things, if they won't eat salmon, olives, pesto, etc etc we think they will NEVER eat them!
Of course, I can list a whole variety of stuff I wouldn't touch as a child, but developed a taste for as an adult. Chilli, curries, olives, Chinese food, raw onions and, obvious as those may be, also strawberries and tomatoes. My mother was/is a great home cook, but we lived on very similar things week in, week out. S&K pie, cauliflower cheese, roast meals, cod in parsley sauce, stews, salads, apple pies and rice puds plus the usual range of "nursery" teas such as boiled eggs, beans on toast, Cheese on toast etc. So we had a good diet, but the levels of variety of today? Today at 35, there is pretty much nothing I havn't tried, and not much I wouldn't eat again. Apart from widgety grubs!
I think that a true fussy eater is probably born.
A fussy easter can also me "made" by reinforcement. Of all the mums I know, there's not one who hasn't at some point been stressed about food. Me included. And I HAVE pretty good eaters. Just some days they won't eat anything (even their favourite dishes) except cheese, or tomatoes, or ANYTHING (except I KNOW they would eat their body weight in chocolate, sweets, icecream given half a chance). The next day they will eat anything offered.
A mothers desire to nourish their children is built in at the core. It begins with the stress and constant discussion about how we feed our newborns, and continues onwards. It gives us pleasure to see our children feed. Sometimes however, this desire can lead us to let them have anything, just so long as they ARE eating.