For purposes of determining premium rates to be charged for personal multi-peril property insurance policies covering real property used principally for residential purposes or any household or personal property that is usual or incidental to the occupancy of any premises used for residential purposes (commonly known as “homeowners” or “renters” insurance), an insurance company authorized to do business in this State shall not treat a child placed in the household by the Illinois Department of Children and Family Services or a private child welfare agency differently from a natural or adopted child of the policy owner. An insurance company authorized to do business in this State shall not consider a policy owner’s acceptance of the placement of a foster child in his or her household as a use of the family dwelling for a business purpose.