Everyone on this earth is born with same type of quality so not possible for a man to born as a manager. The person makes themselves according to their interest and if they are able to mix authenticity with work then have the capability to became a good manger or whatever he or she want so I think good managers could be made not born.
The main important qualities which a manager should have are
1. Leadership
2. Futuristic vision
3. Communication skills
4. Organizing skill
A person cannot get all this qualities in d 2 yrs of management studies only those who have this qualities form before hand can brush up this skills in the period of 2 years of management studies so I feel that one cannot become a manager just by enrolling into an mba course between they should have this qualities in them so I feel they are born.
Time is somehow matter to become what we want. But remember nothing is possible. If someone not able to become good manager then their must be some lack inside him. They don’t want to find it but they simply cheats from himself that they cannot do this.
So any thing can be possible Good manager may born or it can become by study.