I believe that LuckOrNOt is correct about discrimination based on disability, in consideration on the latest ADA (2008) guidelines (an excerpt from 
Americans with Disabilities Act Amendments Act of 2008  is quoted below; although proving that a disability was the reason for not being hired can be very difficult. )
 
"SEC. 4. DISABILITY DEFINED AND RULES OF CONSTRUCTION.
  (a) DEFINITION OF DISABILITY.—Section 3 of the Americans with  Disabilities Act of 1990 (42 U.S.C. 12102) is amended to read as  follows:
  “SEC. 3. DEFINITION OF DISABILITY.
  “As used in this Act:
   “(1) DISABILITY.—The term ‘disability’ means, with respect to an individual—
 “(A) a physical or mental impairment that substantially limits one or more major life activities of such individual;
  “(B) a record of such an impairment; or
  “(C) being regarded as having such an impairment (as described in paragraph (3)).
“(2) MAJOR LIFE ACTIVITIES.—
 “(A) IN GENERAL.—For purposes of paragraph (1), major life activities  include, but are not limited to, caring for oneself, performing manual  tasks, seeing, hearing, eating, sleeping, walking, standing, lifting,  bending, speaking, breathing, learning, reading, concentrating,  thinking, communicating, and working.
  “(B) MAJOR BODILY FUNCTIONS.—For purposes of paragraph (1), a major  life activity also includes the operation of a major bodily function,  including but not limited to, functions of the immune system, normal  cell growth, digestive, bowel, bladder, neurological, brain,  respiratory, circulatory, endocrine, and reproductive functions. "