What is a contralto?
The contralto or alto is the lowest female voice type.
In the industry there are many women who have been classified as altos in their choir, though their voice type is really that of a mezzo-soprano or soprano. This is due to the lack of true altos. This practice can be very detrimental, especially for young girls who strain their voices in order to sing lower than they can, potentially doing irreversible damage.
In a choir, contraltos sing the supporting melody to the sopranos. This doesn't mean that contraltos aren't as important. On the contrary, without the harmony that the altos create, music becomes quite sparse. Also, because true altos are hard to find, a true alto has greater chances of a solo or successful audition in comparison to a soprano.