The thread about parents living with grandparents . . . 100 years ago half of all Americans lived on the farm . . . several generation on one farm. Did the IRS argue about income distribution and deduction distribution between the generations? Was there an IRS 100 years ago? These days housing costs can be half of a family's budget. These days young working adults are not moving out and young parents are moving back in with grandparents. In other words, social conditions are regressing 100 years or more. Tax law needs to be changed to consider multi-generational families but only Congress can change it.