Randy...It is protected and you cannot discriminate because of weight, color, religion, class, sexual orientation and all the rest But what you can do like we have done is set a list of qualifications and make sure everyone gets a background and credit check and make sure that everyone who rents from you is treated the same they must be able to pass the background check.

You just have to make sure you're not approving/declining an applicant based on race, color, sex, religion, creed, national or ethnic origin, age, familial or marital status, handicap or disability or sexual orientation.  

She claims that the dog will help her get out of the house to walk, and that she was sexually abused in the military.

We do not discriminate against persons because of race, color, religion, sex, handicap, familial status, national origin, age, sexual orientation, or gender identity.

Landlords that are blatantly violating the law (slumlords, sexual harassment, violence, etc.). 

Credit, criminal, sexual offender list.  

This is the DE wording in 4603(b)(3), the Delaware Fair Housing Act: (3) To make, print or publish, or cause to be made, printed or published any notice, statement or advertisement, with respect to the sale or rental of a dwelling that indicates any preference, limitation or discrimination based on race, color, national origin, religion, creed, sex, marital status, familial status, source of income, age, sexual orientation, gender identity or disability, or an intention to make any such preference, limitation or discrimination.

I'm curious about screening for applicants who are registered sexual offenders.

In Redding, CA the drug addicts shooting up heroin in the parks was so bad rather than arrest them, they removed the playground equipment, and the public libraries in many towns are overrun with sexual predators using the computers.

Aside from engaging in assault, sexual assualt, or openingly engaging in some illegal activities.