The hand-lettered sign outside the door to P.S. 166 on Manhattan's Upper West Side said "PTA Meeting Thursday." To be exact, it was a parent group that would be meeting, not the PTA.

The sign was proof of the extent to which "PTA" has become a generic term, like "Kleenex" or "Xerox." Many parents are unaware of just how far the century-old National Congress of Parents and Teachers (known since 1924 as the PTA) has strayed from its origins in social uplift or from the classic 1950s-era image we may still have of it--an organization devoted to school service, fund-raising (think of those bake sales and Halloween Carnivals) and wholesome parent-teacher relations.

In fact, the PTA has been losing members steadily for almost a half-century now, from a high point of more than 12 million in the early 1960s to a current membership [now of less than 5 million] and still declining every year. Today only about a quarter of K-12 schools in the U.S. have a PTA chapter. The reasons for this decline are familiar ones: money and politics.

The PTA had its beginnings in an era of women's clubs and settlement houses, when affluent, idealistic women went to work bettering the conditions of the urban poor. Although women still couldn't vote, they could exercise influence through thousands of civic organizations and social clubs around the country. Soon enough, they cast a critical eye on the conditions of children in the public schools. They sought to address such matters as nutrition and hygiene and to help Americanize the offspring of immigrants arriving in waves from southern and eastern Europe.

In 1897, the members of the first National Congress of Mothers--the name of the group that would eventually become the PTA--saw their mission as fostering "a love of humanity and of country . . .and the advantages to follow from a closer relation between the influence of the home and that of the school." The president of the national PTA declared at a recent convention: "We simply must change the country." What happened?

In "The Politics of the PTA" (2002), Charlene Haar explains that the PTA shifted its focus mainly because of its longstanding alliance with the National Education Association. Formed in 1857, the NEA once shared the parent group's concern for schoolchildren in such matters as school curriculum and the qualifications of public-school teachers. Indeed, in 1920, the National Congress felt so much in line with the NEA that it moved into the association's impressive Washington headquarters. Already allied with the teachers group on support for a "progressive" curriculum that would emphasize "life skills," the PTA would from then on curb its more general social programs and limit itself to matters directly affecting education.

By the 1960s, the PTA was known as "a coffee-and-cookies organization"--unquestioningly offering its seal of approval to the newly unionized NEA. It was the issue of teacher strikes, though, that dealt the reputation of the PTA its final blow. In 1961 the AFT, representing New York City's teachers, staged the nation's first citywide strike, and in 1968 Florida teachers followed with the first statewide strike. To avoid conflict, the PTA abandoned any pretense of independence and supported the walkouts.

A few years later, the PTA tagged along with the NEA, lobbying for a cabinet-level federal department of education. What followed were a series of legislative victories for the teachers unions. Among their outstanding lobbying successes, backed by the PTA, was the defeat of a bill co-sponsored by Sen. Patrick Moynihan in 1978 proposing a tax credit for as much as half of private-school tuition. In the aftermath, many parents began their exodus from the PTA, including a large number of Catholics whose tuition fees for parochial schools would have become less burdensome under the plan.

Today the PTA supports all of the union's positions, including increased federal funding for education and opposition to independent charter schools, to vouchers and to tuition tax credits for private and religious schools. This "parent" group lobbies for teachers to spend less time in the classroom and to have fewer supervisory responsibilities like lunchroom duty. Moreover, they want a pay scale for teachers that is based on seniority, not merit. In November, the PTA even helped to defeat California's Proposition 74, which called for limiting teacher tenure by extending the probation period for new teachers from two to five years, a proposal designed to give administrators more time to weed out bad instructors.

With polls indicating that the union label is a liability with the public, an arrangement has developed whereby the NEA provides needed financial support for the PTA, which in turn bolsters union positions at the grass-roots level. As one union official put it: "[T]he PTA has credibility . . . we always use the PTA as a front."

Not only does the PTA support the NEA on issues that protect the public-school teachers' monopoly, the parent group also speaks up in favor of the NEA's more radical curriculum ideas, like sex-education programs that replace "don't" with "how to" and that propose the inclusion of a gay/lesbian unit starting as early as kindergarten.

Many parents have decided that they no longer want to fund this kind of nonsense: They feel that their dues money would be better spent close to home, on after-school programs, computers and school supplies. As the PTA becomes increasingly irrelevant to the lives of children in public schools and parents become less willing to pay its dues, it is gradually being replaced by alternative, mostly home-grown, organizations that may call themselves guilds or councils or associations but are generally known as Parent Teacher Organizations--PTOs. These groups collect no dues and follow no political line.

Tim Sullivan, a Massachusetts entrepreneur and former New York City public-school teacher, saw the need among the independent groups forming around the country for the kind of information and services once provided by the PTA. In 1999 he founded a company for independent parent-teacher groups. PTO Today publishes a magazine and maintains a Web site that provides opportunities for parent networking on its message boards. Both in print and online, PTO Today answers the kind of questions that parents of public-school children ask--how to organize a family night, how to raise money for extras like arts-and-crafts supplies and what kind of insurance is necessary for field trips. With any luck, the PTOs will put the PTA out of business entirely.

Ms. Kramer's books include "Ed School Follies: The Miseducation of America's Teachers" and "Maria Montessori: A Biography."