Dear Uma, I cant really tell you exactly what you should say for this question, but I can give you an idea. My own impression is that the question is not intended to make you doubt yourself but to get an idea about your own motivation and desires. Why did you choose to study mechanical engineering? Was it because you really liked the subject matter? Were you always interested in pulling things apart and putting them back together, or did your parents push you into it? If they did push you into it, are you glad now that you chose the field? Some people will tell you that mechanical engineering is not a good career for a girl. Did you consider this, and if so what made you decide to go for it anyway? If you didnt consider it, do you just have a really supportive family that encouraged you to follow your dreams wherever they might lead? Have you found it to be difficult? Do you believe being a woman is a barrier? I believe the interviewers would be most impressed if you could answer this question honestly and with confidence. If you think you made a bad career choice, your lack of confidence will show in your answer. If you believe you can do the job as well as any man, that will show in your answer as well so dont let yourself be intimidated. Good luck!