Kern County had the highest teen birth rate in California in 2008 even as births to teen moms dropped to a record low in the state as a whole.

The statistics, released Monday by the California Department of Public Health, show the rate of births among teen mothers in Kern County was 64.9 for every 1,000 females, up from 63.8 the previous year.

In Kern, 2,285 babies were born to teen mothers in 2008.

Yet even as Kern's teen birth rate increased, California's fell from 37.1 births per 1,000 females in 2007 to 35.2 births per 1,000 in 2008 -- lower than ever before.

"This is a great day for California. Unfortunately, Kern County is missing out on the celebration," said Norman Constantine, a clinical professor of public health at UC Berkeley and the senior scientist at the Oakland-based Public Health Institute.

Constantine said poverty and ethnicity are often factors in high rates of teen pregnancy. But Kern County is a "mystery," he said.

Something else is happening "on the ground" here that cannot be explained by those other factors, Constantine noted.

Yes, it's true that Hispanic teens continued to have the highest birth rate in California at 56.9 per 1,000 while the rate for whites was 13.1 per 1,000.

But white teens in Kern gave birth at 2 1/2 times the rate of whites statewide, he added.

"You can't blame it on poverty either," he said, citing a higher unemployment rate in Fresno County and a significantly lower teen pregnancy rate of about 55 births per 1,000 females.

Kern's high rate of teen births carries costs to society as well as to taxpayers, said county Public Health Director Matt Constantine, who is not related to the Berkeley researcher. Those costs include higher medical costs for teen births, public assistance costs and costs for increased foster placement.

"Kern's high rate of teen pregnancy presents a significant and ongoing cost to our community," Constantine said. "There's also a cost to those newborns."

According to Denise Smith, Kern's assistant director of disease control, infants born to teen mothers have a higher incidence of complications due to premature birth.

"There's a higher chance those babies will not do well," she said. Which translates into a higher likelihood that costly intervention will become necessary.

One successful program the county has operated is the Nurse-Family Partnership, which offers education and pre-natal support to first-time mothers, Constantine said.

But it does not address the prevention of teen pregnancies.

That job -- if you can call it that -- falls to parents and schools.

At one time, California was the only state that rejected abstinence-only funding from the federal government, said Ken August, a spokesman for the state Department of Public Health. As a result, California has been able to present more comprehensive sex-education to the state's high school students.

And that is directly attributable to the state's dramatically declining teen birth rate, which has been cut in half since 1991 when it was more than 70 births per 1,000.

During the last 10 years, birth rates decreased among both younger and older teens, according to August. The decline was largest among younger teens.

When will Kern County be able to join in the celebration?

"I think we really need to be talking with the teens and the people closest to them, the parents, teachers, social workers and others," researcher Constantine said.

"I suspect local expectations and norms may be factors," he said. "I don't know how else to explain it."