There are no state or federal laws against most opposite gender siblings sharing a room in their own home, but some institutions do regulate how spaces are shared.
When it comes to children sharing rooms, the relation of the children and the context in which they are sharing a room often determines whether there are or are not legal regulations for parents and guardians to consider.
Families considering fostering a child will have to meet certain housing requirements, which vary from state to state.
Many states require older children of different genders to have separate rooms. In Montana, for example, children five and older who are of different genders must be in separate rooms.
These housing requirements often include the number of children allowed to share a single room. For example, the following states have these regulations for shared rooms:
In addition to the number of children allowed to share a room, children must also have their own beds, and the spaces must be safe and comfortable. Houses must also meet other specified housing requirements.
Depending on your state, local housing codes can regulate how many people are able to live in an apartment, condo, etc. For families, these codes may determine if multiple children can share a room, or if those children need their own rooms (e.g., no more than two people may share a given room).
Except for special and/or extreme circumstances, there are no laws specifying how siblings share a room, even siblings with different genders. However, there are laws and regulations when it comes to non-siblings sharing rooms.
How a family decides to share a living space depends on many factors. Different cultures in different regions and times have different norms when it comes to children sharing rooms, and a parent's preferences for their children can depend on many unique considerations.
Some parents simply want their children to learn social skills by sharing a room with siblings. Others want their children to have their own space for privacy. Still others think different genders should be kept apart. In most cases (except for the situations we discussed above), it is ultimately up to each individual family.