42 U.S.C. § 3605
(a) In General.--It shall be unlawful for any person or other entity whose business includes engaging in residential real estate-related transactions to discriminate against any person in making available such a transaction, or in the terms or conditions of such a transaction, because of race, color, religion, sex, handicap, familial status, or national origin.
(b) Definition.--As used in this section, the term "residential real estate-related transaction" means any of the following:
(1) The making or purchasing of loans or providing other financial assistance--
(A) for purchasing, constructing, improving, repairing, or maintaining a dwelling; or
(B) secured by residential real estate.
(2) The selling, brokering, or appraising of residential real property.
(c) Appraisal Exemption.--Nothing in this title prohibits a person engaged in the business of furnishing appraisals of real property to take into consideration factors other than race, color, religion, national origin, sex, handicap, or familial status.