The law protects employees and requires employers, subject to certain limitations, to provide reasonable accommodations. The law in this area can be complex, and you are dealing with your employment so there can be long lasting ramifications. More facts than should be disclosed here on the internet is needed, and some research into the employer and how similar cases have been resolved may also be needed.
I strongly recommend that you speak to an attorney about your specific situation to protect your rights.
DISCLAIMER: This answer is provided in response to a "hypothetical" question and provided for general, informational purposes and does not create an attorney/client relationship. The information presented is not legal advice and may change based additional information and research. It is recommended that you speak to an attorney to discuss your specific legal issues.
As prior counsel indicated, discrimination claims are treated on a case-by-case basis. A number of factors may account for the employer's failure to accommodate your request for a reasonable accommodation. First, the employer might not truly understand your disability. Second, your request might not have been clearly stated as a request for reasonable accommodation. Third, your request might impose an undue hardship. Apparently, your employer needs people to work certain hours; your coworker might have the daytime only spot because she asked for it first, and it would be cost prohibitive to have a second daytime only person. Or, her job might be different than yours in some essential way.
I'd suggest you contact counsel for assistance.
Jay M. Wolman
Jay M. Wolman, Esq.
D'Angelo & Hashem, LLC
6 Beacon St., Suite 505
Boston, MA 02108
(617) 624-9777 (ph)
(617) 624-0999 (fax)
Admitted to practice in MA, NY & DC
The information presented in this response is not intended to form an attorney-client relationship nor is the colloquy protected by an attorney-client privilege or work-product rule. The answer provided is based solely on the minimal facts presented in the inquiry and represents only a preliminary and hypothetical response and analysis. It is not to be considered as legal advice and is for information purposes only. If you wish specific legal advice and recommendations about your particular situation, contact an attorney to schedule a consultation. This is not intended to constitute legal advertising or solicitation, but rather to educate.