If a doctor is so obsessed with his or her work that 80 hours per week is a vacation, then I would recommend against having children. It would not be fair to the kids. However, if the physician does not have children, and is single or has a supportive spouse who is also a workaholic, then go ahead and work 80-120 hours per week if that is what floats your boat.
I am willing to work 65 hours or so per week (not counting oncall weekends), but I want a family, and therefore some balance in my life. A career is not everything. I do not believe that a doctor has to sacrifice any semblance of a normal life for medicine.