ON OUR OWN: Unmarried Motherhood in America.<i> By Melissa Ludtke</i> .<i> Random House: 456 pp., $25.95</i>

For politicians and pundits attempting to score easy political points with the electorate, the terms “unwed mother” and “teen mother” are largely interchangeable. In real life, they are not.

While greater and greater numbers of children are born each year out of wedlock, most of them--more than two-thirds--are not born to teen mothers. Despite the endless yammering on TV talk shows and at political conventions about babies having babies, there isn’t a teen pregnancy epidemic. In fact, the number of teen mothers is dropping dramatically. The teen birth rate fell 8% between 1991 and 1995. It might seem impossible to believe, but according to Melissa Ludtke in “On Our Own,” there were fewer teenage mothers in 1995 (513,000) than there were in 1956 (525,000).

What has changed is the marital status of these teen moms: In 1956, 85% were married; in 1994, 24% were. This is certainly a dramatic change, one that has prompted cultural conservatives, from William Bennett to Robert Bork, to decry American society as a modern Gomorrah. But as Ludtke makes abundantly clear, the causes and consequences of unwed motherhood are far more complicated than the finger-pointers would suggest.

“On Our Own” is a perceptive study based on extensive interviews with several dozen representatives, ranging from poverty-stricken teens to real-life Murphy Browns, those successful career women in their 30s and 40s who are suddenly eager to have kids of their own, on their own. Ludtke is one of the latter. A former writer for Sports Illustrated and Time (and the woman who famously sued for equal access to the men’s locker rooms of the nation), she found herself in her late 30s consumed by the desire to have a child, though there was no man in her life. She started her book in part to understand her own (ultimately fruitless) quest and in the event has written a powerful disquisition on a subject that has usually inspired little more than vague platitudes and table-pounding.

Tired of a debate in which “unmarried mothers are people about whom much is said and concluded, but from whom very little is heard,” Ludtke gives her subjects the chance to speak up. “On Our Own” draws upon the work of sociologists, family experts and Ludtke’s own experiences. But the book owes a great deal to the interviews, conducted over several years, with women in the Boston area and to Ludtke’s attempts to discover how and why they got pregnant, how they were raising their children and what they were doing about the problem of the missing dad.

Unmarried mothers are more than mere victims. Most of the unwed mothers that Ludtke spoke to wanted to be mothers, and most of them aren’t interested in getting married.

For the Murphy Browns, for example, motherhood is a rational decision: These women, though older than most mothers and lacking the support of stable male figures, tend to be in a much better financial (and emotional) position to care for the children they struggle so diligently to conceive.

The prospect of motherhood is considerably more fraught with difficulties for teen girls. Ludtke discovers that countless numbers of teen girls long, sometimes desperately, to become mothers. Getting pregnant is an exciting, even glamorous, act of defiance, however self-defeating it is in the long run. In an attempt to impose a certain order on their often disorderly world, a great number of teenage girls try to get pregnant or simply let it happen to them by avoiding birth control. The prospect of getting pregnant and the reality of being pregnant concentrate teen minds, providing girls who lack ambition and hope with new purpose. They have to get their lives together because they’ll be living for two.

And there is nothing like pregnancy to capture the attention of one’s friends and the adult world. Girls who have lived unexceptional lives, girls whom “people tend to forget . . . because they forget about themselves,” as one observer tells Ludtke, suddenly find themselves at the center of attention. Parents and teachers sit up and take notice; there are special programs for them at school. Other girls look upon them with something akin to awe. Their pregnancies transform them from girls into women. The irony, of course, is that though motherhood wins for teen girls a certain respect from parents and peers, it is in other ways a trap.

As Ludtke points out, this is not the first time that young women have discovered that some forms of liberation are only short-term. After rushing to the altar with an eagerness that seems almost ludicrous, many young brides in the 1950s discovered that trading the paternalism of stern parents for the paternalism of a stern husband wasn’t exactly a route to personal fulfillment, and it’s hardly surprising that the rush to marriage in the 1950s helped to inspire a rush to divorce in the decades that followed. Today, of course, girls are more wary of marriage but not of motherhood. And many of those who hastily abandoned their unhappy childhoods for the prospect of an adult life as a mother are discovering how profoundly limiting such a life can be.

Unwed teenage mothers are often accused of “selfishness,” if not sin, and to a degree the accusation has some validity: A 14-year-old mother, if she is lucky, may recover from her mistake by managing to finish school despite the odds, but life for her child will certainly be more difficult than if she had waited. As Ludtke points out, children of these mothers are more likely than other children to do less well on school tests; more likely to drop out of school; to end up unemployed, on welfare, in jail. Some 60% of the children of unmarried mothers live below the poverty line. And while politicians may complain about the strain these children put on our social services, no one suffers quite so much from these early births as the children themselves. Even worse, it becomes a vicious circle: These children are also likely to have children when they are too young to handle it.

But harping too much on the “selfishness” of the unmarried teen mother is to miss the point. In many ways, the problem of these girls is that they are not selfish enough. Their refusal to marry is a good sign. They know all too well that being trapped in a hasty marriage with an immature and often resentful father is far from heaven. But they still feel compelled to measure themselves by how well they serve the needs of others, in this case, their new babies.

“On Our Own” is profoundly sad in many ways. Ludtke’s stories, in all their messy details, suggest just how misguided and even dangerous political solutions to the problem of unwed teenage motherhood have been. Ludtke is rightly critical of politicians’ penchant for moralistic hectoring from afar. Young mothers, particularly young African American mothers, tend to tune out the demand to wait, especially when “the people and institutions delivering these messages are regarded by the girls as ‘outsiders’ who aren’t going to do any more than talk to--or, even worse, lecture--them about how postponing motherhood will improve their lives.”

What should we do? I find that the solutions proposed by politicians are often contradictory: Gov. Pete Wilson calls for stricter enforcement of statutory rape laws in California as a way to discourage male irresponsibility and the exploitation of teen girls. Meanwhile, Orange County social workers decide to “help” teenage girls in their charge--some of them as young as 13--to marry the men who have impregnated them. (In these situations, social workers have been empowered to take the young girls into custody and to prosecute the fathers, many in their 20s.) Some of the girls in Ludtke’s sample have good reasons for not wanting to marry, even when their prospective husbands are not statutory rapists.

President Clinton thinks one solution to the problem is to force teen moms to live with their parents, though in many cases it is their neglectful or abusive parents who these girls are trying, through pregnancy, to escape. Indeed, one University of Washington study found that a substantial majority of teen mothers--about 66%--had been abused as children. Wouldn’t they and their children be better off on their own?

Other solutions, as Ludtke makes clear, are based on little more than pure political frustration. Conservatives roundly blame welfare for “subsidizing illegitimacy” and teenage motherhood, even though countries with sturdier social safety nets than ours actually have fewer teen pregnancies. Conservatives also blame sex educators for “encouraging promiscuity,” though studies show that easier access to, and more openness about, birth control leads to responsible sexual behavior.

The best contraceptive of all, as Ludtke quotes Marian Wright Edelman of the Children’s Defense Fund, “is a real future.” The only way to convince girls to wait, Ludtke argues, is to provide them with clear and compelling alternatives and to give them the permission, even the courage, to stand up for their rights. Most of these girls just haven’t seen that there are other, and better, ways to take control of their lives than getting pregnant. Perhaps “On Our Own,” by pushing the discussion in the direction of good sense and away from an endless cycle of blame, can help some of them to find these ways for themselves.