The Fair Housing Act passed in April 1968, a week after Martin Luther King Jr. was assassinated — Lyndon Johnson used the political window to push it through a Senate that had killed similar bills for years. It makes it illegal for landlords, real estate agents, lenders, sellers, and homeowners associations to discriminate based on seven protected classes: race, color, national origin, religion, sex (including sexual orientation and gender identity after Bostock), familial status (having children under 18), and disability. The 1988 amendments added familial status and disability; 2020 HUD guidance extended sex to LGBTQ+ identity.
Discrimination doesn't have to be obvious to be illegal. Refusing to rent to you outright is one form, but so are steering (suggesting you'd be happier in a different neighborhood), claiming a unit is "just rented" when it isn't, charging you a higher deposit than other applicants, applying screening criteria selectively, or running ads with discriminatory language. Texas Department of Housing v. Inclusive Communities Project (2015) confirmed that disparate-impact theory also applies — neutral-sounding policies that fall hardest on a protected group can be illegal even without intent.