I apologize in advance for the long post. I just a bit of a nerd when it comes to singing and voice.
Imagine this: A man sings a line from "Ole' Macdonald". Then, a woman sings the exact same line at the exact same pitch, exact same octave. Which line is alto and which line is tenor? Really, neither of them. They are just pitches sung by voices. Alto and tenor are just classifications that make it easy to divide choirs and group numbers with harmony into sections. In a peice of choral or group music, there is often a tenor line, and an alto line, soprano line, etc. They are just guidlines. They can also be voice types, example: "I am an alto" or "I am a tenor", however, these parts have never been sex specific. It just so happens that men on average happen to have lower voices, while women on average happen to have higher ones. But I have met many male alto's in my life, whether they be young boys, or grown men with really high voices. I have also met women who have very low speaking voices that could be classified as tenors. A tenor is not automaticly a man, nor is an alto automaticly a woman.
In regards to choir or group singing, if you are asked to sing the tenor line, or the alto line in a piece of music, it says nothing about the type of voice you have. It merely says that the director or conductor would like you to sing that part of the music for one reason or another. Men are often asked to sing the alto line, and women are often asked to sing the tenor line, as this is the area of crossover between the two sexes. Sometimes a conductor just needs more voices or more sound on a particlar part. I don't think it's unusual, or anything to worry about.
Updated On: 10/17/05 at 07:33 PM