The answer below is based on my personal experience.
Unless, you have a very strong inclination inherently, I think most of the interests are developed in the students by their teachers. If the teachers are good, the students will develop interest in the subject. I was most interested in physics in my high school because our teacher was really good. I was most interested in history in middle school, because our teacher was very good.
I was fortunate to have good teachers in IIT Delhi, but there were a few who were not that great in their teaching, so none of my classmates (that I know of) did their B. Tech. projects in those subjects. Tells you something about how teachers shape the future of students in any stream, including engineering.
We are minimizing the role of teachers in the society. When I was younger, never, not even once, did my father take my side when my teacher was saying something bad about me in school. It did not happen once. My father took my teachers' side, always. The parents are really spoiling their kids by arguing with the teachers in front of the children. It really puts wrong impressions in the minds of the kids. This attitude then percolates when they reach college and treat their teachers with no respect or even disrespect.
I like to blog about various topics ranging from education in IITs to social issues in India and US. All opinions and views presented here are my own and not of my employer.