There are some questions that phrased one way, can be illegal, but phrased in another way, are completely legal for an interviewer to ask. Below are some of those questions:
If someone inquires about your national origin/citizenship:
Illegal: Are you a U.S. citizen? Where were you/your parents born? What is your “native tongue”?
Legal: Are you authorized to work in the United States? What languages do you read, speak, or write fluently? (This question is all right as long as this ability is relevant to the performance of the job.)
If you are asked about your age:
Illegal: How old are you? When did you graduate from _____?
Legal: Are you over the age of 18?
If you are asked about your marital/family status:
Illegal: What's your marital status? Who do you live with? Do you plan to have a family? When? How many kids do you have? What are your child care arrangements?
Legal: Would you be willing to relocate if necessary? Travel is an important part of the job. Would you be willing and able to travel as needed by the job? (This question is okay, as long as ALL applicants for the job are asked it.) This job requires overtime occasionally. Would you be able and willing to work overtime as necessary? (Again, this question is okay as long as ALL applicants for the job are asked it.)
If you are asked about your affiliations:
Illegal: To what clubs or social organizations do you belong?
Legal: List any professional or trade groups or other organizations that you belong to that you consider relevant to your ability to perform this job?
If you are asked personal questions:
Illegal: How tall are you? How much do you weigh?
Legal: Are you able to lift a 50-pound weight and carry it 100 yards, as that is part of the job? (Questions about height and weight are not acceptable unless minimum standards are essential to the safe performance of the job.)
If you are asked about disabilities:
Illegal: Do you have any disabilities? Please complete the following medical history. Have you had any recent or past illnesses or operations? If yes, list and give dates. What was the date of your last physical exam? How's your family's health? When did you lose your eyesight? How?
Legal: Are you able to perform the essential functions of this job with or without reasonable accommodations? (This question is okay if the interviewer has thoroughly described the job.) As part of the hiring process, after a job offer has been made, you will be required to undergo a medical exam. (Exam results must be kept strictly confidential, except medical/safety personnel may be informed if emergency medical treatment is required, and supervisors may be informed about necessary job accommodations, based on the exam results. Can you demonstrate how you would perform the following job-related function?
If you are asked about if you have an arrest record:
Illegal: Have you ever been arrested?
Legal: Have you ever been convicted of ______? The crime should be reasonably related to the performance of the job in question.
If you are asked about military service:
Illegal: If you've been in the military, were you honorably discharged?
Legal: In what branch of the Armed Forces did you serve? What type of training or education did you receive in the military?