THE SAD REALITY these days is that speculative tenancies in common (TICs) threaten to wipe out economic and racial diversity in San Francisco.

That's why Assemblymember Mark Leno's A.B. 781 is so vital to our city's future. The legislation requires that someone own a building for five years before he or she can invoke the state Ellis Act to go out of the business of being a landlord.

In San Francisco, the Ellis Act is generally used by real estate speculators to evict all the renters in a building so that it can be sold to individual buyers as a tenancy in common. In the case of two- and three-unit buildings, for instance, that means two or three people jointly owning a property that each can then occupy a unit in. Later the buyers enter the condo-conversion lottery in order to become owners of their units. It's a win-lose situation: The speculator walks away with a huge profit. The buyers get homes. The displaced tenants – in many instances seniors, people of color, people with AIDS, or working-class folks – have to shuffle for a new place in a market where the rents are still immorally high.

Leno's bill is aimed at cutting out the speculator. It is not, as SFSOS, Plan C, and other organizations are alleging, an attempt to eradicate home-ownership opportunities for the 10 percent of San Franciscans who can afford them. Leno wants to stop lower-income tenants from being displaced by individuals who are not trying to create homes but rather huge profits for themselves. In the process, these greedy individuals are also gentrifying neighborhoods and destroying race and class diversity.

Consider my neighborhood in the Castro, an area that has been ground zero for TICs because it is home to a lot of two-unit buildings. A recent study by the AIDS Housing Alliance revealed that 65 percent of those evicted under the Ellis Act in 2003 were seniors or low-income people with AIDS. Many of those evictions were of people with AIDS who lived in the Castro in two-unit buildings. These are the folks getting the boot so that middle-class white gays and lesbians can have homes in the world's most infamous gay ghetto.

At a Feb. 18 A.B. 781 press conference at Francisco and Powell Streets in North Beach (the site of an Ellis Act eviction), San Francisco Board of Supervisors president Aaron Peskin said speculative evictions were breaking up neighborhoods. As he spoke, the evicted tenants from one of the flats were literally piling their things into a moving van waiting at the curb. A perfect photo op for the tremendous human cost of TICs SFSOS and Plan C never talk about.

The other reality proponents of TICs as home ownership refuse to see is that by creating such expensive housing in neighborhoods (the average price tag is still well over $500,000), TICs also drive up the value of the real estate. Which means that eventually all the working-class people will be forced out. In the Mission District that usually translates into Latinos and artists being displaced; in the Castro, low-income people with AIDS; in North Beach, elderly folks or Chinese tenants. The real price of TICs: San Francisco's rich diversity.

There's no denying that more home-ownership opportunities need to exist in San Francisco. But they shouldn't be created on the backs of working-class and poor folks of all colors and ages who can least afford to relocate. Let's build new condos, establish community land trusts and co-ops, and otherwise find creative ways of providing affordable home-ownership opportunities for everyone, not just a select few. Let's stop cannibalizing the rent-controlled housing stock for TICs. Let's provide homes without contributing to gentrification and displacement. San Francisco's future diversity depends on it.

Tommi Avicolli Mecca is a longtime radical southern Italian queer activist, writer, and performer who comes from a working-class background.