By the way, I don't think age or sex are inhibitors to these traits.

Secondly, unless you're an attorney you probably shouldn't be giving legal advice without at least having a disclaimer or showing some examples of case law in order to prove your point.Here's a link to The Fair Housing Act:http://www.justice.gov/crt/about/hce/title8.phpand here's the specific section that I believe, although I'm not an attorney, proves my point.Sec. 804.[42 U.S.C. 3604] Discrimination in sale or rental of housing and other prohibited practices As made applicable by section 803 of this title and except as exempted by sections 803(b) and 807 of this title, it shall be unlawful-- (a)To refuse to sell or rent after the making of a bona fide offer, or to refuse to negotiate for the sale or rental of, or otherwise make unavailable or deny, a dwelling to any person because of race, color, religion, sex, familial status, or national origin.

I'm just concerned about liability if perhaps a tenant was a sex offender and we did not catch that due to not performing a background check.

I am not an lawyer (and I do not play one on TV ;-)) but I went looking on masslegalhelp.org and found this nugget on Federal public housing:Federal public housingIf you are applying for federal public housing, a housing authority  must deny your application if it finds that:A household member is currently engaged in illegal use of a drug, or the  Housing Authority has reasonable cause to believe a household member's illegal  use of a drug or pattern of illegal use of a drug may threaten the health,  safety, or right to peaceful enjoyment of the premises by other residents.1 The Housing Authority has reasonable cause to believe that a household  member's abuse or pattern of abuse of alcohol may threaten the health, safety,  or right to peaceful enjoyment of the premises by other residents.2   Importantbefore denying a person housing based on illegal drug use or alcohol  abuse, a housing authority may consider evidence of rehabilitation3.Any member of your household is subject to a lifetime registration  requirement under a state sex offender registration program.4 Any household member has been convicted of the manufacture or production of  methamphetamine in federally assisted housing.5 Any household member has been evicted from federally assisted housing for  drug-related criminal activity within the past three  years.6   ImportantA housing authority can also let your household in if the person who  engaged in the drug-related criminal activity has  successfully completed a supervised, approved rehabilitation program, or if the  circumstances leading to the eviction no longer exist—for example, the household  member has died or is in jail.7 In addition to the automatic denials listed above, a housing authority  may deny applicants "whose habits and practices reasonably may  be expected to have a detrimental effect on the residents or the project  environment."8 This means that a housing  authority has wide discretion over whom it allows  into its federal public housing programs.

But the iPad being better than sex?

Been there done that, season rentals have more sex appeal than positive cashflow.

Some offices in my area now are requiring two people per bedroom, regardless of age or sex.

One day, word gets out that lots of kids have been abused at the neighbor's daycare.The families of the abused kids sue the HOA for giving you permission to run an illegal business that hired sex offenders.

I know I can't discriminate when comes to possible tenants but when I do the background screen do I can put a disclaimer or something saying I don't rent to sex offenders, people with mental illness or with police records?

Nicole Curtis is a great example of someone doing it right regardless of sex.