And sometimes if an applicant is close I’ll waive one (ex not quite 600 credit score, but very close).You cannot by law turn down an application due to an emotional support pet,disability, family structure, age, gender, race or any other protected class.Likely he’s just threatening you.  

I think “they” is gender binary lol. 

If permission is given then proceed to attempt to get the vertically challenged, age diminished individual to look up from their smart phone.7) Using Gender Neutral language verify if the child has shifted their attention from their phone to you.

Discriminatory PracticesPolicyAds must not discriminate or encourage discrimination against people based on personal attributes such as race, ethnicity, color, national origin, religion, age, sex, sexual orientation, gender identity, family status, disability, medical or genetic condition.

You can't actually know that the people you are advertising to are X-Y age, Z gender, and so on.

Instead, advertisers will be able to create a Special Ad Audience, an audience based on similarities in online behavior without considering things like age, gender or ZIP code.

Or can it be up to the current tenants if they're fine with living with the opposite gender?

Recently, my male and female tenants in one property are not getting along and I need to address this.I think if I rent my room-by-room properties out to one gender less tenant issues will occur.Have you experienced this in your business?

Frankly, I have never cared what the gender, race, religious, sexual orientation etc ever when choosing a company.

The four factors that impact real estate prices, availability, and investment potential are: Demographics     Interest Rates    Government Policies & Subsidies    The EconomyFirst: DemographicsDemographics are characteristics of a population: its age, race, gender and income levels; the kinds of jobs held by inhabitants — and so on.