In general the increased number of people in a home leads to more wear and tear and increased utility usage. Bigger people tend to make more noise although there are some babies and toddlers who are certainly very loud and run around a lot. In Canada, it is not unheard of to share a room with your baby but typically after the baby is a year or more they tend to have their own room. When it comes to Canadian landlords, parents having their younger children sharing a room is not necessarily preferred but may not be an issue especially if the child is a baby. When the children are toddlers then landlords prefer that children have their own room. If applying for a rental that will be considered. In terms of housing and social services, an 8 or12 year old are considered older children. Landlords would not want or expect that the children and parent share the one bedroom. Social services would also find it unacceptable for the children of that age and parents to share a room. Nobody is likely to report the family because of the arrangement. It would only be an issue if social services was already involved with the family. That may change if one of the children is male and that they continue sharing a room. In general teenagers of different sexes are supposed to have separate rooms and preteens and teenagers are not supposed to share rooms with their parents.