D.C. Code tit. 2, ch. 14 § 2-1401.03

(a) Any practice which has a discriminatory effect and which would otherwise be prohibited by this chapter shall not be deemed unlawful if it can be established that such practice is not intentionally devised or operated to contravene the prohibitions of this chapter and can be justified by business necessity. Under this chapter, a “business necessity” exception is applicable only in each individual case where it can be proved by a respondent that, without such exception, such business cannot be conducted; a “business necessity” exception cannot be justified by the facts of increased cost to business, business efficiency, the comparative characteristics of one group as opposed to another, the stereotyped characterization of one group as opposed to another, and the preferences of co-workers, employers, customers or any other person. The business necessity exemption is inapplicable to complaints of unlawful discrimination in residential real estate transactions and to complaints alleging violations of the Fair Housing Act, approved April 11, 1968 (42 U.S.C. § 3601 et seq.) (“FHA”).

(b) Nothing in this chapter shall be construed to bar any religious or political organization, or any organization operated for charitable or educational purposes, which is operated, supervised or controlled by or in connection with a religious or political organization, from limiting employment, or admission to or giving preference to persons of the same religion or political persuasion as is calculated by the organization to promote the religious or political principles for which it is established or maintained.

(c) Nothing in this chapter shall be construed to supersede any federal rule, regulation or act.

(d) Nothing in this chapter shall prohibit any religious organization, association, or society or non-profit organization which is operated, supervised or controlled by or in conjunction with a religious organization, association or society from limiting the sales, rental or occupancy of housing accommodations which it owns or operates for other than a commercial purpose to members of the same religion or organization, or from giving preference to these persons, unless the entity restricts its membership on the basis of race, color, or national origin. This chapter does not prohibit a private club, not open to the public, which incident to its primary purpose, provides lodgings which it owns or operates for other than a commercial purpose, from limiting the rental or occupancy of these lodgings to its members or from giving preference to its members.

(e) Nothing in this chapter shall prohibit an employer, an employment agency, or a labor organization from seeking, obtaining, or using genetic information to determine the existence of a bona fide occupational qualification reasonably necessary for the normal operation of an employer’s business or enterprise; provided, that the employee or applicant for employment provides, in writing, his or her informed consent, the genetic information is provided to the employee or applicant for employment in writing as soon as it is available, and the genetic information is not disclosed to any other person.

(f) Nothing in this chapter shall prohibit an employer from seeking, obtaining, or using genetic information about an employee to:

(1) Investigate a workers’ compensation or disability compensation claim; or

(2) Determine an employee’s susceptibility or level of exposure to potentially toxic substances in the workplace; provided, that the employee provides, in writing, his or her informed consent, and the genetic information is provided to the employee in writing as soon as it is available, and the genetic information is not disclosed to any other person.