You are correct about Baltimore and other areas in that the landlord is responsible for screening the prospective tenant for criminal record, sex offender, etc...

It's important to look at a nationwide report because they might have been convicted of an offense or be on a sex offender list in another county or state and you deserve to know that before renting to them.Another powerful screening tactic is to get an address history report so you can compare their actual residential history with what they claim on their application.  

We use screening company to verify previous addresses, please list accurate information so we can speak to your previous landlord(s).Criminal History - No felonies, or sex offenses, drug trafficking, violent crime, terrorism, burglary, theft, arson, vandalism.

I want to make sure you thoroughly understand this piece since you are going it alone.The Fair Housing Act prohibits discrimination against prospective tenants and current tenants on the basis of the following characteristics or "protected classes": race, color, religion, sex, national origin, disability, and familial status.

Have dinner with her at your place, watch a movie with her at your place and have sex at your place but then send her back to her parents house afterwards.  

The fact is that vast majority of sex offenders will always be a danger which is why you are probably safe to say you will not rent to known sex offenders.

Here is the Seattle definition: “Discrimination” means any conduct, whether by single act or as part of a practice, the effect of which is to adversely affect or differentiate between or among individuals or groups of individuals, because of race, color, creed, religion, ancestry, national origin, age, sex, marital status, parental status, sexual orientation, gender identity, political ideology, honorably discharged veteran or military status, alternative source of income, participation in a Section 8 or other subsidy program, the presence of any disability, or the use of a service animal by a disabled person.

Or any of them could be a sex offender.  

I've owned student rentals for 24 years and there are too many potential issues, when you just "shove" people together especially of the opposite sex.  

The key is not to discriminate on ethnicity, sex, age, sexual orientation, disability ect.