For many Americans, marriage held a very important status in society, it was a sign of maturity and financially stability. To these people, marriage is supposed to be between a man and woman with each sex in their separate gender sphere. Similarly, these people also believe that the only sexual identity is heterosexuality, and that any other sexuality is unnatural. The reason for this belief is that many people still hold near and dear the old theories of sexuality, however, these theories no longer have the same value that it used too. As theories of sexuality change so must people change too. To understand how theories of sexuality has changed over the decades, one must trace the changing of sexualilty from sexology in the 19th and 20th century