(a) An agency in any branch of state government may not hire a person as an employee if the person is of the age and gender that would require a person residing in the United States to register with the selective service system under federal law, unless the person presents proof of the person's:
(1) registration with the selective service system as required by federal law; or
(2) exemption from registration with the selective service system.
(b) This section does not apply to a person employed by a state agency before September 1, 1999, as long as the person's employment by the agency is continuous.