Here’s what happens with Boy Sopranos.
When they reach puberty, the vocal cords (folds) actually undergo a PHYSICAL change. They actually become thicker (hence the emergence of the “Adam’s Apple”) It is not known in advance whether the boy will become a tenor or a baritone until the voice actually changes.
The Muscles involved in Vocal training are not located in the larynx, but in the Pelvis, abdomen, upper and lower back, and the muscles between the ribs, called the Intracostals. These muscles, if they have been conditioned properly, do not lose their conditioning just because the voice has changed. Nor does the knowledge of technique and theory, or the reading of music. So, if the boy likes his “new” voice, he can continue training (once the weirdness has gone away!) and become a great singer. BUT, Of course, he will be BOOTED out of the “Boy Soprano Choir” no matter how magnificent his new voice has become. (This happened to one of my students. I told him not to worry, he didn’t need no steenking choir to sing! LOL)
I have had 15 years of vocal training myself, and have been teaching for another 12 since then. :-)
Thanks for asking...This is my favorite subject of discussion.
I love your explanation. Much better than my daughter’s. (She considers me a lightweight in music and talks down to me.)
My daughter had to start all over with her voice training once she had a Cesarean section. They cut those muscles and it took years to get them back in shape. She still has a beautiful voice, but I’m not sure that she can hit that high note in Mozart’s Alleluia any more. She ducks the question every time I ask.