Anatomical differentiation of human vestibular hair cells begins by 8 weeks gestation.
Fetal cochlea hair cell differentiation starts two weeks after vestibular hair cells.
Afferent innervation of the neuroepithelium occurs before hair cell differentiation.
Vestibular hair cells and calyx afferent fibers are functional by mid gestation.
PAX2, SOX2, and SOX9 in human fetal cochlea show graded spatiotemporal profiles.