Why the list matters more than the label
Fair housing questions almost never ask whether discrimination is wrong. They ask whether the facts fall inside the statutory list. The federal Fair Housing Act works by naming classes, and conduct is unlawful only when it is because of one of those named classes. So the first move on any question is to match the facts to a class.
The seven protected classes
42 U.S.C. 3604 protects seven classes: race, color, religion, sex, national origin, familial status, and handicap (disability).
Count them, because the exam tests the count directly. Five was the count from 1974 to 1988, before handicap and familial status were added by the Fair Housing Amendments Act of 1988. Nine is the trap for candidates who add sexual orientation and gender identity as separate classes. Six matches no version of the statute at all. The current answer is seven.
Familial status includes pregnancy
Under 42 U.S.C. 3602(k), familial status protection expressly extends to any person who is pregnant or in the process of securing legal custody of a minor. So a manager who refuses a unit to a woman because she is seven months pregnant and he thinks children are disruptive has committed familial status discrimination.
The trap is answering sex, which tempts because only women become pregnant. The statute places pregnancy squarely within familial status. Handicap is wrong too, because pregnancy is not treated here as an impairment that substantially limits a major life activity.
Sexual orientation and gender identity
HUD's February 11, 2021 memorandum, implementing Executive Order 13988, directs HUD and its FHAP and FHIP partner agencies to enforce the Act against discrimination because of sexual orientation and gender identity as forms of sex discrimination, relying on Bostock v. Clayton County, 590 U.S. 644 (2020).
That is enforcement policy nationwide, not a new statutory class. Only Congress can amend the list, which remains seven. It is also not limited to HUD-assisted housing; that narrower idea belongs to the Equal Access Rule at 24 CFR 5.105.