Historically, only a few professions existed. Members of the clergy, medical doctors, and lawyers held the monopoly on professional status and on professional education, with military officers occasionally recognized as social equals. Self-governing bodies such as guilds or colleges, backed by state-granted charters guaranteeing monopolies, limited access to, and behavior within, such professions.
With the rise of technology and occupational specialization in the 19th century, other bodies began to claim "professional" status, such as engineers, paramedics, plumbers, and teachers. Today almost any occupational group may, at least unofficially, gain professional status, and with unification and hard work, they may even become a recognized profession.
To gain status as a recognized profession, an occupation must be governed by some nationally chartered organization or guild that sets guidelines for education and certification required of its members. These organizations have written ethical standards and require their members to abide by them. These organizations set and enforce high standards of conduct and professional behavior so the public may have a high level of trust in a professional that is a member of the organization. Think about the respect and trust earned and held by members of the American Bar Association or the American Medical Association.