i’m just gonna quote a couple of sections from the conclusion of the survey here that actual statisticians wrote after analysing their own data:
When having children is viewed as hampering the pursuit of one’s career, self-development, or financial goals, as a capstone to be achieved once these other goals have been reached, women’s wishes for children, or for the number of children they consider ideal, may be deferred to the point of permanence.
… only women with considerable financial resources at their disposal feel confident about pursuing larger families. As a result, and perhaps uniquely among industrialized societies, Canadian fertility outcomes and intentions are highest among the wealthiest women.
research should also focus on more tractable issues such as housing costs or family policy, including child care