The federal ADA requires employees to prove as part of their prima facie case that they can perform the essential functions of the job they hold or seek, with or without reasonable accommodation. Put another way, if they can't do the job regardless of accommodation, they cannot claim discrimination under the ADA.
The California FEHA is broader than the ADA in many respects. Lower courts were split on whether the employee had to prove they were qualified - that they could perform essential job functions with or without accommodation. In Green v. State of California, the court of appeal held that employers, not employees, had the burden of proof on this issue. That is, the lower court said that employers must show the employee was NOT able to perform essential job functions with or without any accommodation.
The California Supreme Court, reviewing Green v. California, held that FEHA is analyzed like the ADA, in that employees have the burden of proving they can perform their essential job functions with or without reasonable accommodation.
DGV