Here is an interesting discussion of children singing opera. He's against. The article is attracting a lot of comments. This is all brought on by Jackie Evancho, a product of the competition program America's Got Talent.
People have asked me about her. She sings stuff like "O mio babbino caro." She's a kid. People like to see children doing things, imitating grownups. She scoops and slides only slightly more than the woman I was complaining about. It bothers me that she tries to sound like an adult singer with the vibrato and lowered larynx. I think that's what anyone is complaining about. No one seems to complain about English boy sopranos, but they never sound like this.
I prefer this aria like this. I like the pictures of the Ponte Vecchio in Florence because she sings that if she cannot marry her beloved she will throw herself off of it
So what about this little girl with a far more grownup voice than Jackie? This kid actually does give me goosebumps.
It is important for people to realize that it is considered unethical for professional voice teachers to teach little children to sing like adults. This is what the argument is all about. 16 is the generally accepted age for beginning serious lessons, which means after puberty.
Beverly Sills and Roberta Peters trained as children. This sample of 8 year old Sills will help you define the problem. This is what a child's voice sounds like.