The risk-benefit ratio of pursuing a career in medicine continues to tip in favor of risk:
1. Overhead costs of practice (the gross salary is not equal to take home pay)
2. Huge (and rising) debts for medical education. My tuition was 22,000 /year on average. It's gone up since then. 
3. Opportunity cost (8 years of education without pay. For further training, I now live in an expensive city, and my salary is just enough to cover my cost of living)
4. No pension or benefits (for most of us)
5. My partner has had to give up his employment opportunities (further HUGE opportunity cost)
6. Risk of not being employed (hear about this more frequently now)

I think it's fair to save my earnings through incorporation. I need to make up for the opportunity cost of medical school, the opportunity cost of the loss of my partner's employment opportunities, a living wage during my working years, and a pension as a retiree. Income splitting makes up for the loss of my partner's income.