There are some things that employers cannot ask about on job applications or during interviews. Laws against illegal discrimination might bar questions such as the ones below. Note, however, that federal discrimination laws usually apply only to employers that have 15 or more employees. But your state or city might have similar laws that apply to smaller employers.
Your application form cannot ask any questions about an applicant's race, including the color of the applicant's skin, eyes, or hair. You also cannot ask the applicant to include a photo of him/herself with the application, because this would indicate the applicant's race.
You cannot ask an applicant about his or her heritage or national origin. That includes questions about what country the applicant came from or "place of birth." You also can't ask whether English is the applicant's first language.
You can't ask if the applicant has a "green card." But every employer of 15 or more employees is required by federal immigration laws to make sure that the applicant can show that he or she can work in the United States - even if the employer has no reason to suspect that the applicant is not a citizen. To do so, the applicant is required to complete an "I-9" form. A copy of that form is available through the Immigration and Naturalization Service.
You may not ask about a job applicant's religion, if the applicant has religious beliefs or what those beliefs are, or what religious days the applicant observes, because those questions are prohibited by laws against religious discrimination.
You may, however, tell an applicant what days the applicant will be required to work. In certain circumstances, you might be required to accommodate an employee whose religion forbids working on certain days.
You cannot ask on the application form if an applicant has a disability - though you are permitted to ask whether the applicant can perform the "essential functions" of the job with or without a reasonable accommodation.
If a job applicant's disability is obvious in an interview, you may not ask you how bad the disability is - unless the question is directly related to the applicant's ability to perform the job. For example, if a hearing-impaired applicant applies for a job where he or she would seldom have to be able to hear well to do the job, you cannot ask you how bad the applicant's hearing loss is. GotTrouble.com