Teen motherhood has gained a bit of celebrity allure with the pregnancies of Jamie Lynn Spears and Bristol Palin, but front-line professionals see a starkly different reality involving poverty, lost opportunities and a cost to taxpayers in the billions of dollars annually.

At minimum, the public cost of births to teens 17 and younger is $7.6 billion a year, according to research presented Thursday at a national forum in Chicago. The calculation includes both the lower taxes that these often impoverished families contribute and the extra social services they require.

"Teen births do have substantial, widespread negative effects, especially for the children of teen mothers," said University of Delaware economist Saul Hoffman, who compiled the estimate.

"The children are more likely to be in foster care, less likely to graduate from high school," he said. "The daughters are more likely to have teen births themselves, the sons are more likely to be incarcerated."

There are more than 400,000 teen births annually in the United States, most of them to unmarried mothers on welfare, according to the National Campaign to Prevent Teen Pregnancy.

Yet over the past year, teen pregnancies have been in the spotlight in contexts detached from the sobering statistics.

TV actress Jamie Lynn Spears, Britney's unmarried kid sister, gave birth to a son at 17. The hit movie "Juno" featured a spunky heroine who remains at high school while pregnant and recruits a married couple to adopt the baby. And Republican vice presidential nominee Sarah Palin disclosed that her 17-year-old daughter, Bristol, was pregnant, would have the baby and would marry the boyfriend.

In each case, the real and fictional teens come from supportive, financially stable families, and seemed to be on track to have an array of future opportunities that a more typical teen mom might lack.

"It's been glorified all over the place," said Evelyn Rodriguez, 34, a New Yorker from a low-income background who gave birth to a son at 15 and now, after more than a decade of juggling jobs and classes, is on the verge of earning a college degree.

"People who don't have the money and great support, they say, 'Oh, wow, they're doing it - it's cool,'" said Rodriguez, referring to Spears and Palin. "But it's not cool. I've been through it. It's a job. I don't appreciate what's going on out there making it seem so beautiful, when it's not."

To the panelists at Thursday's forum, organized by the University of Chicago's Chapin Hall Center for Children, the hoopla over Spears and Palin represents a squandered opportunity for a serious national discussion of teen motherhood.

"We are, as a society, uncomfortable with sitting down and having conversations about what we expect," said Sarah Brown, director of the National Campaign to Prevent Teen Pregnancy. "When is the last time we said, as a culture, 'Babies need adult parents.'"

Brown's organization and its allies have deepening concerns because of the latest federal statistics on teen births. After 15 years of decline - attributed both to less sexual activity and more use of contraceptives - the teen birth rate increased 3 percent between 2005 and 2006, and a further increase is expected when the 2007 figures some out soon.

Brown said the cost estimates contained in Hoffman's research could be useful in persuading policy makers to be more aggressive in trying to reduce teen births.

"We wish we could interest them on grounds of human suffering alone," she said. "But when our issues have dollars attached to them as well, it does make a difference."

Hoffman's findings are contained in a new book, "Kids Having Kids: Economic Costs and Social Consequences of Teen Pregnancy." He said his calculations of costs to taxpayers were based on the difference between bearing a child at age 17 or younger and delaying childbearing until at least age 20.

He described his new cost estimate of $7.6 billion annually as conservative, and said the total cost to society could be more than three times as high. A previous study by the Campaign to Prevent Teen Pregnancy pegged the annual cost to taxpayers at $9.1 billion.

Less than 40 percent of the mothers who have their first child before age 18 earn a high school diploma, Hoffman writes, and their children are far more likely to go into foster care and eventually end up in prison than children born to even slightly older mothers.

Yet the executive director of a New York nonprofit that assists teen mothers, Linda Lausell Bryant of Inwood House, said government financial support can be hard to come by because of negative attitudes.

"These girls are seen as to blame for where they are - even though many of them were molested or raped as they were growing up," Lausell Bryant said. "The girls tell us all the time they experience tremendous judgment - they're under a cloud of suspicion."

Many of the girls served by Inwood House had already dropped out of high school before they got pregnant, and see motherhood as a chance to add meaning to their lives.

"It's a dream of raising a child the way they wish they'd been raised - being the kind of mother they never had," Lausell Bryant said. "That's the fantasy - it's very powerful."

The vast majority of the girls are black or Hispanic, adding to Lausell Bryant's frustration over the Spears-Palin phenomenon.

"It's a double standard," she said. "If you're a poor kid of color, it's a bad thing. If you're affluent and white, it's not so bad."

Rodriguez, who spent years in Inwood House programs, later helped the organization by mentoring a younger generation of pregnant girls. She says many of the recent clients are linked to gangs - either as members or as girlfriends of members - and lack any basic knowledge of contraception.

"When you don't have information, you're more of a target," she said.