Fair Housing Act: Passage and Amendments

On April 11, 1968, President Lyndon Johnson signed the Fair Housing Act into law, prohibiting housing discrimination on the basis of four protected classes: Race, Color, National Origin, and Religion.
The original Fair Act identified only four ‘protected classes’ (Race, Color, National Origin, and Religion). Six years later in 1974, Sex was added as a protected class.
The Fair Housing Amendments Act of 1988 added Familial Status (i.e. families with children) and Disability as protected classes. Design and construction requirements would make multifamily housing accessible going forward.

https://www.fairhousingfirst.org/fairhousing/history.html