Hi Dr. Rassman,
There are two well-designed, peer-reviewed studies demonstrating the efficacy of dutasteride in preventing male pattern baldness:
In addition, here is a peer-reviewed case study:
I hope this convinces you of the efficacy of dutasteride in preventing male pattern baldness, even relative to finasteride.
The general consensus for dutasteride is that it grows hair. I do not believe other doctors will challenge this point too much. The real question is how much better it is when compared to finasteride. And more importantly is the safety profile of the drug and the issues of side effects when taken for an indefinite period of time. Dutasteride has a very long half life in the order of weeks versus finasteride which has a half life in the order of only hours.