Exposure to phthalates during development can also cause malformations of the male reproductive tract and testicular cancer.

FORBES: Connect

In humans the vocal tract acts as a filter on the sound from the source, and the "source-filter theory" held that the separate, fine control of the vocal tract to be the product of a long evolution in the development of the subtleties of speech.

BBC: Helium-huffing gibbons 'sing with soprano technique'