Today he would go to prison as a sex offender.

@JR T This article says, "Courts have long held that hiring on the basis of sex is permissible where sex is a bona fide occupational qualification in the context of serving privacy interests." 

It's discriminatory because you are biased to wanting a family and are discriminating against adults who are not a traditional family.The Fair Housing Act, which is the federal law governing housing discrimination, includes the following seven protected classes: race, color, religion, national origin, sex, disability, and familial status.I think you are technically right, that normally people get in trouble for discriminating against children than toward them, but better to set up your processes and posts so that you are blame free.

I'll come say hi while I'm staying in Mountain View later this week.A successful RE investor once told me "Sex and real estate, get a lot while you're young."

Her son was about to get out of prison and register as a sex offender.

Over the past few years my business (sex therapist) has really taken off.   

I can see some in here having a non-premarital sex clause.

Placing strangers together can have challenges even when people are the same age and sex, but mix up those variables and it can get ugly.I was at fair housing training and we were specifically told even advertising housing as "college housing" is discriminatory, because it implies families are not welcome.One other caveat, if YOU are owner occupying the property, you can legally discriminate against the other occupants.

Some allow for tenants to reimburse expenses with CAM.

If you run background checks on the existing tenants you would likely find outstanding warrants and felons and maybe even sex offenders (depending on the location).