The single family home was an artifact of the blue model world. Before World War II, it was common for many generations of a family to live together. Before social security, grandparents didn’t have the money for independent living; children and grandchildren were a safety net. Often, extended families would live together, sharing chores, cooperating with child care and other activities.But postwar suburbia changed all that: each nuclear family was supposed to be an island unto itself, and zoning laws in many American cities and towns changed to make illegal the kind of multi-family living that had once been the norm.That is changing these days, and once again it makes sense for many generations of a family to live together. Whether it is grandparents living into their 80s and 90s (something that was once rare but is now increasingly common), or single parent households where the parent needs help from other adults to raise kids, or the growing number of households where grandparents have to step in and provide the home that parents can’t or won’t offer—American living patterns are moving away from the nuclear family model of the Leave It To Beaver era.To accommodate those changes, we need to change zoning laws. Multiple families need amenities like more than one kitchen in a house, something that, as this Wall Street Journal article notes, is verboten in many communities. That needs to change; we need flexible zoning laws that fit the way our society is moving.That isn’t all: zoning laws in many cities and suburbs also limit or even prohibit the use of a home for business. This, too, is a relic of the Peak Blue postwar era. The nuclear family in its suburban paradise wasn’t supposed to do any work in the home. The family was limited to the sphere of consumption; production was supposed to take place in factories and offices far, far away from domestic bliss.But that makes less and less sense in an era of self-employment and Ebay. Actually, government policy needs to reduce the hurdles for people who want to develop their own businesses: a kitchen big enough to turn out the food for a home catering service, a workshop for small appliance repair, neighborhood-based day care, Airbnb rentals of spare rooms, the list goes on. Just as in 19th century America, when most Americans lived on a farm, the family’s residence was also the source of its livelihood, so in 21st century America the family enterprise will need to make a comeback. Like the 18th century blacksmith, whose forge was in the back yard, or the grocer whose family slept above the store, 21st century Americans are going to be blending the worlds of production and consumption.From zoning laws (and some restrictions will still be needed with an eye to safety, noise, pollution and congestion) to tax law changes that would promote the business use of a home, to social and urban planning policy, we need to be thinking now about the changes that will make it easier for the American people to discover and create the jobs and careers of the future. Allowing the home, the most expensive and valuable asset most Americans have, to become something that meets more needs and is even a platform for generating income, is one piece of the policy mix that can jump start the middle class renaissance that America so badly needs.