RNE Interview

Introduction: Did you know that one of the most critical problems that the transgender person presents is the voice? Throughout the last decades the concern for the problems of the voice has gone from considering a medical care to an extraordinary directed to professionals of the voice or elite singers to be part of the concept of health. There is a growing demand for a higher, more feminine vocal tone. The largest group corresponds to that of transgender women, who want to feminize their voice.

Dr. Juan Carlos Casado, what is the feminization of the voice?

Hello good afternoon, voice feminization basically consists in increasing the vocal tone, in increasing the frequency with which that voice is produced. To understand voice feminization  we have to make a small anatomo-physiological memory of human phonation. There is an acoustic parameter called fundamental frequency and this is the number of times the vocal cords open and close per second. We, depending on the fundamental frequency, can distinguish a stereotypically masculine or stereotypically feminine voice. There is a “magical” number that is 165 Hz, such that a voice above 165 Hz is perceived as a stereotypically feminine voice and below 165 Hz is perceived as a stereotypically masculine voice. For example, the listeners will be listening to me and will perceive a male stereotyped voice, the fundamental frequency of my voice is 137 Hz. So in the voice feminization what is intended is to increase the vocal tone, increase the frequency of the voice above of 165 Hz.


And who are the people who demand us to increase the fundamental frequency of the voice?

As you said, basically the most numerous group is that of transgender women. But not only are transgender women, there are also cis women – that is, women whose sex is according to their gender – and they have endocrine disorders that have an excess of testosterone, which for example can be the Morris syndrome, the Klinefelter syndrome, Polycystic ovarian syndrome. But undoubtedly the most frequent group is that of transgender women. Probably some listener will be wondering, and the voice feminization can not be achieved with a hormonal treatment? Well the answer is totally negative. In the same way as testosterone, that is, androgens if they produce a vocal tone below 165 Hz, however, the use of estrogen, the use of 17 beta estradiol does not affect the voice at all. If it would alter for example the breast development, the disposition of the hair in the body, but it does not affect at all the vocal tone. That is why we must give an answer to transgender women who want their voice to be in accordance with their body, in short: voice feminization.


And how do you do that? How is the voice feminized?

Well, the voice is feminized with a method that we have designed and we are pioneers in Spain, which consists of a surgical technique plus post-operative speech therapy. Surgical technique consists of converting an anatomically male larynx into an anatomically female larynx, producing a shortening of the vocal cords, decreasing the mass of the vocal cords and increasing the tension of the vocal cords. This is done with a surgical technique called Wendler’s Glotoplasty with a personal modification resulting from the experience of approximately 6 or 7 years ago, which we have been reviewing. After performing the surgical technique, post-operative speech therapy is very important. For this, a speech therapist from our team called Soledad Angulo Serrano, is responsible for modifying the vocal gesture. And why do we have to modify the vocal gesture? As I said at the beginning, the fundamental frequency, the vocal tone, is what we can perceive if a voice is masculine or feminine, but there are also other factors, such as intonation, resonance, laryngeal articulation, kinesia, which is the way of speaking. All this constitutes what is called the vocal gesture. The modification of the vocal gesture is done with speech therapy. So the surgeon, in this case me, what I do is modify the shape of the larynx and the speech therapist what she does is modify the vocal gesture.


Remember in the book “Feminization of the voice: multidisciplinary approach of the transgender woman” collects the knowledge available today on this topic and helps the transgender woman to understand in a global way the journey undertaken by her in her transition.