The vocal cords or vocal folds are two sets of tissue stretched across the larynx. They can vibrate when air passes through the larynx. This produces sounds. Humans use them to produce language.
Men and women have different vocal fold sizes. Adult male voices are usually deeper: males have thicker cord. The male vocal folds are between 17 mm and 25 mm in length.[1]
The female vocal folds are between 12.5 mm and 17.5 mm long.
The difference in vocal fold size between men and women means that their voices have a different pitch. Each person's voice is different and has a slightly different pitch. This is caused by genes that influence how the larynx is made.