In January the Supreme Court decided that merely having a problem (carpal-tunnel syndrome, in the particular case) that hinders you in performing your specific job does not qualify you as disabled under the ADA. In late February, the Supreme Court heard oral arguments on a case involving Chevron's desire to not have someone with Hepatitis C (which can adversely affect the liver's ability to handle toxic chemicals in the body) working for them recycling waste oil, an often toxic-laden endeavor.
In earlier cases, appeals to the highest court in the land were required to ascertain that it was legal for United Airlines to not hire nearsighted women as pilots and for the Albertson's supermarket chain to fire a truck driver who was nearly blind in one eye.
One potential legal doctrine, apparently too startling for either the Supreme Court or the overwhelming majority of congressmen who passed the ADA, could cut through the tangled Gordian knot of ADA litigation. It's the notion that an employment relationship does not constitute enslavement on either side. Unless the employer and employee have contracted otherwise, someone should be able to fire you for any cause they deem valid-just as you should be able to quit for any whim of your own.