Voice is crucial for gender identification during the transition process, as voice feminization plays a significant role in the success of passing. In order to be able to classify the role of voice treatment during the interdisciplinary gender reassignment process of MzF-trans*, possible recommendations for action for the cooperation with the medical doctors are needed. Four expert interviews from the disciplines of otolaryngology, endocrinology, and plastic surgery were conducted to establish a potential guideline consensus for the role of speech-language pathology as an interface to the male-to-female gender reassignment process. Based on the expert interviews, it is uniformly recommended that voice treatment should be considered early in the transition. Primarily, conservative therapy should be considered to avoid e.g. irreversible surgery of the larynx. The focus of voice treatment in voice feminization is centrally on the adaption of the speaking fundamental frequency. In postoperative cases, speech-language pathology is intended to adapt the speech pattern to the new anatomy and prevent complications, such as uneconomic voice and speech. The current interviews represent a first insight into the cooperation between speech-language pathology and the medical specialties for the treatment of MzF-Trans*. In order to implement the recommendations from the preliminary expert interviews for a potential guideline consensus, consultation with involved professional societies and more randomized trials of specific voice treatments in MzF-trans* are needed.