Therapy has been shown to be effective in voice feminization, and the modification of certain voice characteristics, such as fundamental frequency and voice resonance, can help in that effect. Fundamental frequency, closely related to pitch, was initially thought to be the characteristic most effective in voice feminization. Raising the fundamental frequency can help towards voice feminization. However, each person might have different perspectives regarding speech and voice, and therefore the salient characteristics, and their relative impact towards femininity, can vary from person to person, and many clients are not satisfied with only a change in fundamental frequency. The efficacy of treatment should therefore be evaluated, not only by acoustic characteristics, but also using the transgender person’s perception of the voice and its femininity.