<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />
do you have a link to the study, because what you linked was a newspaper article about the research? i couldn't find anything linking the study on line, which suggests that it hasn't been published, which in and of itself casts its integrity into doubt.
you're right, though, that it is remarkable that the article and researcher don't mention the incomes of families, considering the *very* remarkable pattern in the use of the canadian family leave program. the incomes of families would have had to be a *major* factor in developing the sample for the researcher to have controled for income; in canada, use of the parental leave program turns out to be almost perfectly inversely proportional to income, particularly in the 0-6 month range. without the study parameters, and considering the income effects on participation in the canadian leave program, it isn't at all reasonable to assume that parents who didn't use any or much leave were not poor or not severely limited in their daycare options by their incomes. without the study to prove otherwise, the op's assumptions are far more credible than yours.
But I didnt give my opinion on the study as of yet.
I am unable ot give legal or medical advice. My opinions are based on my experiences and my personal research.