What major aspect does the Fair Housing Act not prohibit?

The Fair Housing Act, established in 1968, is designed to prevent discrimination in housing-related activities based on certain protected classes, including race, color, religion, sex, national origin, familial status, and disability. However, it does not address discrimination based on citizenship status. Therefore, the correct answer highlights that discrimination based on an individual's citizenship status is not prohibited under the Fair Housing Act.

In contrast, the other options involve aspects that are explicitly prohibited. Racial discrimination is one of the primary concerns of the Act and is directly addressed in the legislation. Age discrimination is also a significant issue in housing, particularly with regard to senior housing, thus it is prohibited in many forms under related laws. Discrimination in leasing falls under the purview of the Fair Housing Act, as it encompasses various aspects of housing transactions, including renting, selling, and advertising properties.