In the 21st century, it is often said by those selling singing
techniques, books and methods that most people can learn how to
sing. In fact, scientists have stated that the human larynx is
typically very similar across all humans with only a difference
in sizes. It is however a commonly held belief that singing is
reserved for only a few which are born with the ability. Because
of the difference in vocal fold sizes, some people are less
capable of hitting higher and lower notes in chest voice (tenor
can't hit much below low c, most untrained baritones can't go
much above middle C). Knowing one's tessitura is important, the
song must be in a key suitable for you, otherwise you are likely
to look quite the fool as you break and go into falsetto or head
voice in inappropriate places. The human larynx is an
instrument, in which all that is necessary in order to sing is
to learn how to use it, and practice often. With a little bit of
motivation and patience, it can be achieved.