@Bao Chau Tran It's definitely not your standard lease.  

This is obviously a roommate situation, but I was under the impression that only an owner-occupied unit creates the ability to discriminate/prefer things such as gender, it doesn't seem right that a tenant can block a landlord from bringing in a new tenant whose sex the current tenant doesn't prefer.Is this right of refusal really extended to other tenants already inhabiting a unit, or does this turn into a Fair Housing situation, where no discrimination can be practiced, since the owner does not live in the unit, merely a tenant who is complaining that she does not want to live with a male.

I am fairly certain you would not dispute that fact however to state that having sex will produce an offspring is speculation.A investment is something that is anticipated to pay a regular return on a ongoing bases.Speculation is based on past practice and involves an assumption that it will repeat in the future.  

In addition to what John said, you can also check out open source sex offender websites.

Best Regards,Bao

I have a certain ratio per100 headcount (not households, not age, not sex) I use when decidingto buy or build in a town.

Our policy is anyone over 18 goes on the lease and gets a background check, if they have a criminal past or sex offender register and they commit a crime you could have some liability in it.

Hi @Jack Bao  Glad you found BP!

And if you want to be in the housing provider business you can not discriminate against individuals based on their race, color, national origin, sex, familial status or disability.

Then I heard about the (unfavorable to men) sex/dating ratios in San Francisco.