Income splitting be should be allowed in all families , business or not ...a working parent making 50 k a year , supporting 2 kids and wife should not be taxed at  the same  rate  as a single person with no dependants ...the income should be spread evenly over all the people it supports ...that is 
 progressive taxation ....ask yourself why we have to  import 250,000  immigrants a year to have population growth ? Cause Canadians cannot afford to have enough children to keep population growing ...think what if 20 years  ago  tax policy made having more children affordable ...our economy would   right now  be dynamically charged   with another baby boom