The ADA has four main components: (1) requirements for maintaining medical records and requiring medical testing, (2) an employer must reasonably accommodate disabilities, (3) an employer may not discriminate against an individual with a disability, and (4) an employer may not retaliate against someone who opposes discrimination of participates in protected activity.
An employer cannot require you to take a medical examination before you are offered a job. Following a job offer, an employer can condition the offer on your passing a required medical examination, but only if all entering employees for that job category have to take the examination. However, an employer cannot reject you because of information about your disability revealed by the medical examination, unless the reasons for rejection are job-related and necessary for the conduct of the employer's business. The employer cannot refuse to hire you because of your disability if you can perform the essential functions of the job with an accommodation.
The ADA has been criticized on the grounds that it decreases the employment rate for people with disabilities and raises the cost of doing business for employers, in large part due to the additional legal risks, which employers avoid by quietly avoiding hiring people with disabilities. Some researchers believe that the law has been ineffectual. Between 1991 (after the enactment of the ADA) and 1995, the employment rate of men with disabilities dropped by 7.8% regardless of age, educational level, or type of disability, with the most affected being young, less-educated and mentally disabled men. Despite the many criticisms, a causal link between the ADA and declining disabled employment over much of the 1990s has not been definitively identified.
Most recently, however, pizza chain Domino's has been brought under suit for their website not being accessible for specialty ordering. The U.S. Supreme Court refused to review the case, instead upholding the decision of the 9th U.S. Circuit Court of Appeals who said the “alleged inaccessibility of Domino’s website and app impedes access to the goods and services of its physical pizza franchises—which are places of public accommodation.”