It's interesting from a scientific point, anyway.
From my POV, it means I really have to get cracking on finishing up those vocal harmony arrangements for my CD.
The reason? My alto is going to become a baritone soon.
Specifically, Dr. Jane Ann Robinson told me today she plans to become Dr. James Daniel Robinson.
We joked that if things take a while, she could cut all the alto tracks, then after her voice changes, she could cut baritone tracks. (Actually, she thinks she'll be a tenor like her father, but I think she'll be a baritone.)