Is there a difference physiologically between singers?

Question

I know that some people can take lessons to improve their voices, stay on key and whatnot. My question is is there an actual difference in the stucture of someones vocal cords which make some singers sing so well. Like Mariah Carey vs. J.LO vs. some american idol rejects vs. Jennifer Hudson. Or is it in their genetic code????? Has science figured out the difference???? Or is there no difference??? Is it in the brain and audiotory system???

Answer 1

It's technique.  Barring some extreme cases, everyone is working with the same equipment.

Answer 2

There are quite a few physiological and mental differences.  Some people are truly better equipped.  Training, practice, motivation, and luck also make a big difference in what you can do with your basic equipment.