I question this guy's expertise. Why would you refer to falsetto as a "fake, artifical" voice so emphatically? Also, I'm not entirely sure I buy the "hormonal imbalance" idea.
start questioning your knowledge altogether. FALSEtto IS an artificial timbre:
Falsetto - Wikipedia, the free encyclopedia
and about the hormonal imbalance controversy - the main problem is that the terms countertenor and falsettist are pretty much unclear everywhere.
Perhaps this can make it clearer to you:
Men Getting High: Falsettists, Countertenors, Pop, Rock, and Opera « Fire and Air
" Countertenor: Guys singing alto. This is what the word itself means, “against and above the tenor,” meaning alto range. The three possible types are:
Falsettist: Guys singing alto in falsetto.
Classical: Andreas Scholl, David Daniels, Michael Chance, James Bowman, Alfred Deller
Pop/Rock: Jimmy Somerville, Brian Wilson, Franki Valli, occasionally Mick Jagger
Again, to many people, countertenor equals falsettist. And not all men’s falsettos sit in the alto range. Some men with extremely deep voices would probably never reach the female registers even in falsetto, and some men with high chest voices may have falsettos that sit in mezzo or soprano. (Such men, such as the aforementioned Jaroussky, are properly called “sopranists.”) Most men’s falsettos, however, land right in the middle of the alto range.
Tenor altino: Guys singing alto in chest voice.
Classical: Russell Oberlin
Pop/Rock: Neil Sedaka, Steve Perry, Art Garfunkel, Smokey Robinson
This is an extremely rare voice type. Note that all are Americans. I’ve tried to list the pop ones in descending order of range; ranking Perry and Sedaka presents a challenge as Sedaka’s range is completely circumscribed by Perry’s. Perry however used his voice much, much more vigorously, causing it to drop it relative to Sedaka while still circumscribing his range. Garfunkel is a half-and-half, sitting directly between high tenor and low alto.
Castrato: Guys singing alto (or even soprano) in chest voice because they have no testosterone and sometimes no balls.
Classical: Alessandro Moreschi, Radu Marian
Pop: Ain’t none
Moreschi was the last of the surviving castrati, who was recorded a century ago when he was 60 years old. The modern-day Marian is believed to have an endocrine disorder. The other best known names are Senesino (alto) and Farinelli (mezzo), but no recordings survive of them.
All other options also require the absence of testosterone by using either a woman or a young boy. The three options above are the only ones for adult males. The first two are the only options for healthy adult males — you were either born with a naturally high voice, or you squeak your way in by using your falsetto (pun not intended but I’ll take it anyway). That’s it.
There’s one other vocalist around that I should mention. His name’s Michael Maniaci, also an American. His voice is very light and high and sits naturally in the soprano register, far above Oberlin and Perry. He’s quite healthy, and unlike Radu Marian, he has no endocrine disorder; his larynx simply never matured for whatever quirk of fate. Consequently, he cannot be considered an endocrinological castrato.
Maniaci was born with a slight facial palsy that resulted in the right side of his face having significantly less nerve insertion that the left and being consequently less mobile. It isn’t terribly noticeable — his features are pleasant and attractive — but if his larynx also has unusual nerve insertion, it may have affected that body part’s ability to respond to his testosterone. Indeed, his voice has transformed partially, but not entirely. As Maniaci himself states, while his “vocal cords did lengthen and thicken somewhat, they didn’t to the extent that most men experience.”
The rest of him, however, most certainly did respond to his testosterone. Maniaci may have the larynx of a castrato, but unlike them, he also has the (rather burly) body of a hormonally normal man. Hence, he does not sound like a castrato. He does not sound like a falsettist, nor does he sound like a typical man, and he doesn’t sound like a woman, either. He could be considered the extreme end of the spectrum represented by the altinos, but he is so radically far above them and so very unique that he really is his own category. "
this bbc doc on castrati talks about the vocal folds behaviour and how do healthy men produce high notes on falsetto
https://www.youtube.com/watch?v=S8ZAraf5wMc