We do not, quite obviously, recommend castrating some group of male babies, foundlings as it often was, in the hope that some of them would be able to sing when they grew up. That is what was done in order to produce castrati though and the question is, well, why?
The answer to that shows us why this is just fine as it is but also why it’s not a perfect solution:
In the world of opera, the question “who wears the trousers?” has suddenly become harder to answer. Looser gender divisions in casting, and a new understanding of the effect of changing hormones on the voice, mean that – for divas in particular – the future looks much brighter. Who is to say only a man should ever sing Puccini’s Nessun Dorma?
If a female singer’s vocal range dips with motherhood or age, she can simply switch to a lower voice, such as tenor. And, says Ash Khandekar, editor of the magazine Opera Now, switching categories across gender divides is becoming more acceptable.
Women with lower – mezzo-soprano or contralto – voices have always been cast in the cross-gender “breeches” roles of the popular opera repertoire, parts such as Cherubino in Mozart’s The Marriage of Figaro or Octavian in Richard Strauss’s Der Rosenkavalier. But now female singers in professional companies, as well as in amateur operatic societies and choirs, are taking advantage of the end of traditional boundaries to call for women to have the opportunity of lengthening their performing careers.
We’re liberals around here, proper classical liberals. Thus what consenting adults get up to is what consenting adults get up to and that’s the end of that. Yea, this extends even to people voluntarily subjecting themselves to Webern and, shudder, musique concrete. So the idea that post-menopausal warblers might hum along in a different register doesn’t bother us in the slightest.
But, but, why the castrati? Because male and female voices differ in more than just register. As the current crop of (non-castrati) counter-tenors show. We’ll let proper experts debate the exact differences but our own interpretation is that voices differ by gender by both register and timbre. The timbre being something that doesn’t change along with the register and age.
Yep, we’d be delighted to hear Figaro sung by one of those deepening female voices but then we’ve delighted in it as sung by Bugs and Elmer as well. But as with the second greatest cartoon ever made* those female voices just won’t be the same as male ones even as they hit the same notes.
*We know the greatest, but do you?