Table 1.

Eligibility criteria.

	Inclusion	Exclusion
Publication type	Randomized controlled trials, non-randomized studies (cohort studies, case control studies and cross sectional studies and quasi randomized controlled clinical trials, case reports) will be considered as appropriate study designs for inclusion. Peer-reviewed studies Published in English No limitation concerning the publication date	Reviews, systematic reviews, meta-analyses Studies which are not peer-reviewed No full text available
Participants	Transgender women: assigned male at birth and female gender identity No age restrictions	Gender non-binary people Transgender men Transgender women who completed phonosurgery
Intervention	Pitch elevation Articulation – resonance Intonation
Intervention outcomes	Fundamental frequencies (fo ) Fundamental frequency range Formant frequencies Vowel space Patient satisfaction Gender perception