Del. Code tit. 6, § 4605

It is unlawful to deny a person access to or membership or participation in any multiple-listing service, real estate brokers’ organization, or other service, organization, or facility relating to the business of selling, exchanging, or renting dwellings, or to discriminate against the person in the terms or conditions of such access, membership, or participation, on account of race, color, national origin, religion, creed, sex, marital status, familial status, source of income, age, sexual orientation, gender identity, disability, military status, or housing status.