and subsequently regulating protein synthesis. The interaction between the endocrine system and tissues such as breast, brain, testicles, heart, bones, etc., is being extensively studied. It has clearly been seen that the larynx is somewhat affected by hormonal changes, but surprisingly, very few studies are working on elucidating this relationship. The effect of hormonal changes in voice is clearly seen when hearing male and female voices, or when listening to a teenage voice changing during puberty. Actually, it is believed that the number of hormonal receptors in the pre-pubertal phase is higher than in any other age. Menstruation has also been seen to influence the voice. In fact, singers are encouraged by their instructors not to perform during their pre-menstrual period, because of a drop in their voice quality. Vocal fold phonatory functions are known to change from birth to old age. The most significant changes occur in development between birth and puberty, and in old age. Hirano et al. previously described several structural changes associated with aging, in the vocal fold tissue. Some of those changes are: a shortening of the membranous vocal fold in males, a thickening of the vocal fold mucosa and cover in females, and a development of edema in the superficial lamina propria layer in both sexes. Hammond et al. observed that the hyaluronic acid content in the vocal fold lamina propria was significantly higher in males than in females. Although all those studies did show that there are clear structural and functional changes seen in the human vocal cords which are associated with gender and age, none really fully elucidated the underlying cause of those changes. In fact, only a few recent studies started to look at the presence and role of hormone receptors in the vocal cords. Newman et al. found that hormone receptors are indeed present in the vocal cords, and show a statistical distribution difference with respect to age and gender. They have identified the presence of androgen, estrogen, and progesterone receptors in epithelial cells, granular cells and fibroblasts of the vocal cords, suggesting that some of the structural changes seen in the vocal cords could be due to hormonal influences. In this specific study, androgen and progesterone receptors were found more commonly in males than in females. In others studies, it has been suggested that the estrogen/androgen ratio be partly responsible for the voice changes observed at menopause. As previously