Why is it possible to identify the gender by the voice of the speaker? That is because male and female voices have different pitches. Our human voice is also a sound wave, which can be described by the physical parameters of sound waves. The physical characteristics of voice include loudness and intensity, pitch and frequency, frequency range and octave, sound quality and frequency spectrum. Tone is an important physical characteristic of voice, which is expressed by the physical quantity frequency, the unit of which is HZ (representing the number of vibrations per minute). Generally speaking, the pitch of low frequency is low and the pitch of high frequency is high. Usually male tone fundamental frequency is 90-300Hz, average 150Hz, voice is lower, sound deep and thick, female voice tone fundamental frequency is 140-430Hz, average 280Hz, tone is higher, sound bright and crisp, children’s fundamental frequency is above 300Hz, sound crisp, bright and penetrating, but the width of the sound range is narrow. During childhood before the age of 7, there is little difference between male and female voices, and during elementary school, there are subtle differences between male and female children’s voices. After puberty, with the secretion of sex hormones, both male and female children go through a vocal change period, and the vocal organs undergo a series of changes, which are manifested by the enlargement of the laryngeal body, the decrease and stabilization of the laryngeal body in the neck, the enlargement of the thoracic and pharyngeal cavities, sinuses and other resonant cavities, and the enlargement, thickening and widening of the vocal folds. With the change of physiological structure, the voice also changes from a child’s voice to an adult’s voice. The pitch of adult women drops 1/3 of a tone scale compared to children, and the tone is fuller than children. The secretion of male hormones (especially testosterone) causes more pronounced changes in the male vocal apparatus, and the pitch decreases by one step, resulting in a lower, stronger and more powerful adult male voice. After puberty, the range of male and female voices is defined. If the voice change process during puberty does not pass smoothly, pitch abnormalities will occur. Because of the greater change in the male voice, pitch abnormalities are more common in males than females. Pitch abnormalities may occur if the unstable voice state at the beginning of voice change is maintained until adulthood, or if the mind is not mentally prepared to change from a child’s voice to an adult voice and refuses to accept a thickened voice. Male voice pitch abnormality is characterized by a thin or unstable voice, intermittent out of tune, sharp and other strange sounds, and also by a constant and habitual increase in pitch, called “male and female pitch”. Female tone abnormalities are manifested as a coarse, low voice, lack of female bright high-pitched, called “girls male tone”. There are relatively few cases of “girl-male” tone, and most of them are boy-like “girls”, while a few may have hormonal abnormalities. We know that a tight string has a high pitch and a loose string has a low pitch, and the vocal cords, as the vocal organs, are similar to the strings. According to this principle, the pitch can be changed by changing the length and tension of the vocal cords. The vocal folds are located in the laryngeal cavity, which has two main pieces of cartilage that form a scaffold and act as the equivalent of an atrial beam, the thyroid cartilage. The vocal cords are indirectly connected to the thyroid cartilage through a number of ligaments and joints. Surgery to change the pitch of the voice is done on the thyroid cartilage, which is superficial in the neck, and the laryngeal nodes in men are formed by the intersection of the thyroid cartilage plates bilaterally, so this surgery is not very invasive. In medical terms, this type of surgery is classified as “thyroid chondroplasty”, which was first proposed by Japanese scholars in 1974 and has been recognized and applied worldwide for the past 40 years, and is a mature surgical procedure. By shortening the thyroid cartilage plate, the vocal folds can be shortened and the vocal folds can be relaxed, thus lowering the pitch of the voice; by closing the distance between the thyroid cartilage and the cricoid cartilage below it, the tense vocal folds can be lengthened and the pitch of the voice can be raised. Generally speaking, we perform vocal fold tension surgery to increase the fundamental frequency by 50-100 Hz and vocal fold relaxation surgery to decrease the fundamental frequency by 50-100 Hz. People who have undergone the surgery feel a significant improvement afterwards, and it is very effective in improving self-confidence and self-affirmation for the surgeon. Of course, to make the voice more perfect, the post-operative training of articulation is needed to make it more natural, round and pleasant in all aspects, such as voice quality, tone and intonation.