Gender-Affirming Voice Therapy: Why Pitch Is Only Part of the Story

Leung, Oates, and Chan's 2018 meta-analysis in the Journal of Speech, Language, and Hearing Research fundamentally reoriented clinical practice. Their analysis of 38 studies determined that speaking fundamental frequency accounts for 41.6% of variance in listener gender perception.

This means nearly 60% of what makes a voice sound masculine or feminine has nothing to do with pitch. Earlier clinical protocols that focused narrowly on achieving ~200 Hz targets were missing most of the picture.

While pitch isn't everything, it's still clinically important. Research has identified specific thresholds that influence gender perception:

For voice feminization: Voice therapy reliably increases mean F0 by 25-40 Hz depending on speech sample type. Schwarz et al.'s 2023 systematic review found spontaneous speech improvements averaging 25 Hz, with reading passages showing 39 Hz improvement. Importantly, session quantity did not significantly influence outcomes (p=0.625)—technique quality matters more than raw session count.

For voice masculinization: Testosterone therapy typically lowers F0 from approximately 180 Hz to 130 Hz over 6-12 months. However, roughly 20% of trans men do not reach cisgender male F0 ranges (≤131 Hz) with hormones alone, necessitating voice therapy intervention.

Formant frequencies—particularly F1, F2, and F3—are approximately 20% higher in cisgender women than men. This difference is too large to be purely anatomical; behavioral factors significantly contribute. The clinical implication is clear: SLPs must target a minimum 20% increase across formant frequencies for meaningful perceptual change.

Beyond pitch and resonance, prosodic features significantly influence gender perception. Wolfe et al.'s foundational 1990 study in JSHD found strong correlations between femininity ratings and specific intonation patterns:

A 2025 randomized controlled trial by Papeleu et al. in JSLHR confirmed that intonation training alone significantly increases femininity ratings—validating that this component deserves dedicated therapeutic attention beyond pitch modification.

Understanding hormone effects is essential for setting realistic expectations and timing therapy appropriately.

ASHA's Practice Portal and multiple systematic reviews identify several validated therapy approaches for gender-affirming voice work.

Telepractice is validated: Lin et al.'s 2023 pilot study demonstrated significant improvements in mean F0, TWVQ scores, and self-perception using a telepractice protocol combining resonant voice therapy, Vocal Function Exercises, and vocal hygiene education. This expands access for clients in underserved areas.

ASHA's Practice Portal and WPATH SOC-8 outline comprehensive assessment domains that go far beyond simple pitch measurement.

For some clients, voice therapy alone may not achieve desired outcomes—or they may prefer a combined approach. The evidence supports synergy between therapy and surgery.

Wendler glottoplasty has emerged as the current surgical standard, using endoscopic suturing of the anterior vocal folds to shorten functional vibrating length. Cricothyroid approximation (CTA), an older technique, shows less predictable results and deterioration over time—many institutions have abandoned it.

For transmasculine clients unresponsive to testosterone, Type III thyroplastycan lower pitch by reducing vocal fold tension. Catani et al.'s 2024 series (13 patients) documented F0 decreasing from 156 Hz to 109 Hz (p<.001).