Let the interviewer know that you don't find the question relevant to the job you're interviewing for, and take that opportunity to share some information about yourself that you DO find relevant, explaining how it illuminates your qualification for the job in question.
Alternatively: look for another job.
Anyplace that makes you uncomfortable at a job *interview* is substantially more likely to make you even MORE uncomfortable once you're showing up there every day.
Trust your spider senses.