The difference in vocal folds size between men and women means that they have differently pitched voices. Additionally, genetics also causes variances amongst the same sex, with men's and women's singing voices being categorized into types. For example, among men, there are bass, bass-baritone, baritone, baritenor, tenor and countertenor (ranging from E2 to C#7 and higher), and among women, contralto, alto, mezzo-soprano and soprano (ranging from F3 to C6 and higher). There are additional categories for operatic voices, see voice type. This is not the only source of difference between male and female voice. Men, generally speaking, have a larger vocal tract, which essentially gives the resultant voice a lower-sounding timbre. This is mostly independent of the vocal folds themselves.