This came up on another Forum I post to. I read the article and listened to the recording - I found it disturbing. I'd known the "castrati" existed but didn't realize it was so relatively recent. This recording was made in 1902, and Alessandro Moreschi was the last performing "castrato".   Apparently a number of parents had their sons castrated in the hopes that they would find fame and fortune as opera singers but most of the unfortunate boys never achieved success. Here's the link:
http://news.bbc.co.uk/1/hi/magazine/4853432.stm