@Michael Jones re your example of the wheel chair ... in California, the landlord is required to accept people with any handicap, but the tenant is required to pay for any necessary modifications, e.g., wheelchair ramp.

So, do (Handicap) Accessible Rental Properties bring in more cash? 

Owner shall pay, except as provided elsewhere in thisAgreement, all expenses incurred by the Agent, including, but not limited to, reasonable attorney’s fees and Agent’s costs andtime in connection with any claim, proceeding, or suit involving an alleged violation by the Agent or Owner, or both, of any lawpertaining to fair employment, fair credit reporting, environmental protection, rent control, taxes, or fair housing, including, butnot limited to, any law prohibiting, or making illegal, discrimination on the basis of race, sex, creed, color, religion, national origin,age, marital status, or mental or physical handicap, provided, however, that the Owner shall not be responsible to the Agent forany expenses in the event that Agent is finally adjudicated to have personally, and not in a representative capacity, violated anysuch law, unless such acts and or omissions are outside the course and scope of Agent’s duties hereunder.

Have you figured out a handicap system yet to this monopoly game?

Do you give handicaps to those posting from their phones?

I guess I'm just mentally handicapped to understand your point.

@John Kunick:  FAR from a 'liberal catch-phrase' and ubiquitous in real estate, nationwide, including your own jurisdiction: Oklahoma Fair Housing LawThe Oklahoma Fair Housing Law (Title 25, article 4A, Section 1451 through article 5, Section 1508) prohibits discrimination in the rental, sales, financing, appraisal, insurance of housing and other housing-related transactions based on the following categories or "protected classes" including race, color, national origin, religion, sex, familial status (including children under the age of 18 living with parents or legal custodians, pregnant women, and people securing custody of children under the age of 18), and handicap (disability).

However, it gets worse for you if the property is MF in the city of San diego. under the city of San Diego tenant protection act, you must pay them 2 months rent or 3 months if they are senior or handicapped.  

One is handicapped and will need care all his life, so I would like to purchase a fourplex type building so he can live in one with a carer, and the rents pay for all his costs etc.

Depending on the type of "group home" (drug/alcohol rehab, handicapped, mental illness, elderly, etc.) you have other laws to make sure you comply with, and great point by David D Painter re insurance.