The Americans with Disabilities Act (ADA) offers protection to individual with disabilities in several ways. Disability discrimination may occur because of a current disability, and it also may occur when a covered employer treats an applicant or employee less favorably because he or she has a history of a disability. And example of this would be cancer that is controlled or in remission. Discrimination may also occur if an indicidual is believed to have a physical or mental impairment that is not transitory and minor – even if he or she does not have such an impairment.
The law requires an employer to provide reasonable accommodation to an employee or job applicant with a disability, unless doing so would cause significant difficulty or expense for the employer (“undue hardship”).
The law also protects people from discrimination based on their relationship with a person with a disability (even if they do not themselves have a disability). For example, it is illegal to discriminate against an employee because her husband has a disability.
Note that not everyone with a medical condition is protected by the law. In order to be protected, a person must be qualified for the job and have a disability as defined by the law.