I don't think this justification will fly in, especially when Canada is very keen on children's growth and giving CCB (Child Care Benefit) to every single family based on their salary. This justification would clearly rip out the hidden intention to the VO."After consulting with our family and some friends in Canada, we decided that it would be extremely difficult to raise a child and also establish a family in a new country. As a family, we have decided for me to settle in Canada first by finding a job in my field with a good salary and a house in a great city and neighborhood. Once that's achieved, I would apply PR for my dependents through Family Class Sponsorship."
But I researched about this to certain extent and it seems this is not a vital point in deciding your application's approval/refusal. You just have to give a reason.