In my line of business, in dealing with family finances and giving advice on how to maximise a salary surplus, I have gained a lot of experience in market segmentation: which family structures generally thrive and which do not.
Statistically, couples who do not have children are financially better off than those who do have children. This need not be so, but in order for a family to thrive, proper financial planning must be done.
If a family does not plan seriously, they tend to spend their entire combined surplus on the children’s needs, to the detriment of other financial needs, such as wealth creation (which benefits everyone, including the children) or retirement funding.