Soupdragon, I know quite a few kids with SN so they are not really that much of a minority. My sister for example would probably love to enter her son in for a 'cutie' competition, but he has Downs so is unlikely to win. And yes, she is afraid of negative feedback. As a mother of a child with a disfigurement of any kind, you know your child is less than perfect, but you don't want other people telling you that.
I see my teenage nieces getting paranoid about their looks, they say that they are too plump, or their noses are too big, or their lips too big, because they are inundated with models in teen mags and on television that are perfect and skinny, with no blemishes or blotches, you hardly ever even see a model wearing glasses! (Unless it's an ad for Specsavers!)
I've seen kids covered in boils, psoriasis, burns, strawberry birth marks, some without hair, etc, etc. Yet they are the most beautiful children inside. But you wouldn't think that they way they are treated by society, most people avoid them like the plague! Personally I would like to see all beauty competitions banned and dummies used to model clothes instead of children. That way we don't get brainwashed about what we perceive as perfection and maybe we'd be more accepting as a society.
But I do understand why mums put their kids into these competitions, we all like to think our kids are beautiful and it's a huge complement to have that confirmed by others. I'm just also too aware of the mums who never get that confirmation.