Del. Code tit. 6 § 4604
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, national origin, religion, creed, sex, marital status, familial status, source of income, age, sexual orientation, gender identity, disability, or housing status.
Nothing in this chapter prohibits a person engaged in the business of furnishing appraisals of real property to take into consideration factors other than race, color, national origin, religion, creed, sex, marital status, familial status, source of income, age, sexual orientation, gender identity, disability, or housing status.
6 Del. C. § 4604