I have one niece that won't eat any vegetables at all
( apart from potatoes, and only then when they are converted into chips )
I have another niece who won't eat any fruit. When I point out the inherent irrationality of that, in that all fruit looks, and tastes differently, I am just met with a sulky smirk.
Both girls are in the 20's.
In my opinion, all this is the fault of the parents, who indulged their kids from a very early age. When I was growing up, we had to eat whatever was put in front us....silly fussiness just wasn't acceptable.