The St. Thomas Boys Choir of Leipzig and other European ensembles of boy choristers increasingly are challenged by the earlier onset of puberty and resulting voice changes among their members. When Johann Sebastian Bach led the St. Thomas choir in the early 18th century, boys’ voices typically broke around the age of 17; now, it’s happening around age 13.
Some researchers speculate that the change is due to improved health and nutrition, The Washington Post’s Michael Birnbaum reports:
http://www.washingtonpost.com/world/europe/leipzigs-st-thomas-boys-choir-deals-with-change/2012/04/07/gIQAYaXC2S_story.html
POSTSCRIPT (APRIL 13): Hope Armstrong Erb, artistic director of the Greater Richmond Children’s Choir, says she and other American youth-choir directors have been dealing with the puberty issue for years.
Erb notes that research, going back some three decades, has found that youngsters in Southern states experience puberty earlier than those in the North. She also speculates that steroids and other chemicals fed to livestock, when passed along the food chain to children, may bring about an earlier onset of puberty.