You have asked a pertinent question, to which most of parents are not able to find an answer. Most parents think that they know a lot about life in general. This is true but they are mostly confused when they have to guide their children about career choices as there are plenty of careers to be pursued these days.
When I was studying in school, there were limited options for career: medicine, engineering, administrative services or doctorate courses. We had no career counselors then; even our parents were not competent enough to guide us in this regard. I just chose medicine over engineering though I had very good marks in mathematics.
Now things have taken a u-turn; there are plenty of careers and counselors, and most parents are competent enough to guide their children as well.
My daughter, who was very good in studies throughout, opted to make a career in accounts, changing the study stream accordingly. I was sure that if she followed a career in medicine, she could do so successfully. But I allowed her to exercise her free will in choosing her career. She completed studies to become a Chartered Accountant and is at present successfully employed in a multi-national audit firm.
I did the same when my son decided to opt for hotel management course. I had allowed both my children to have their will in choosing their career.
It is futile to pressurize children to follow the career choice that their parents decide. It is more valuable to know their interest and help them choose accordingly rather than imposing your own choice. Children are quite smart these days; they are more knowledgeable than their parents in some respects.