Really interesting article from Washington Post. We have the same debate in Stockholm, whether duplexes or triplexes should be allowed in areas with only one family houses, or not.

In Minneapolis, much of the opposition has come from residents who already own single- family homes. A related factor, springing from the debate over income and density, has been race and the role that single-family housing plays in keeping housing segregated.

As cities rethink single-family zoning, traditional ideas of the American Dream are challenged - The Washington Post