"To see 26 states with statistically significant increases is fairly remarkable," says Paul Sutton, a demographer with the National Center for Health Statistics, which released the data Wednesday. "We're seeing increases in both the number of teens having births and also the rate at which they are having births. Both of them are going up."

The federal data — largely from birth certificates — shows widespread statistically significant increases for 2006, the most recent year for which data are available. In the two previous years — from 2004 to 2005 and from 2003 to 2004 — only one state in each year (Tennessee and South Dakota) had a significant increase.

These state-by-state breakdowns add to previously released data from the national center that complete the picture for 2006, a year in which the general fertility rate hit its highest level since 1971 and one that ended a 34% drop in births among women ages 15-19 from 1991 to 2005. In 2006, the teen birth rate increased 3%, to 41.9 births per 1,000 women ages 15-19.

At the time, observers said they'd have to wait for 2007 data to know whether 2006 marked a blip or a reversal of the downward trend.

But now, the new state-by-state data gives credence to the idea that the downturn in birth rates is over, says Kristin Moore, a senior scholar at the nonprofit Child Trends.

"It occurred among teens 15-17 and 18-19 and among whites, blacks and Hispanics, and now we know it occurred in most of the states," says Moore, who has tracked teen births for 30 years. "It appears to be quite a general pattern, which makes me think it might not be a blip but a turn-around."

The highest teen birth rates are in the South and Southwest; Mississippi is highest with 68.4 per 1,000, followed by New Mexico, with a rate of 64.1 and Texas, with 63.1. The lowest rates are in the Northeast. New Hampshire had the fewest teen births with 18.7 per 1,000. Vermont, with 20.8 per 1,000, and Massachusetts, with 21.3 per 1,000, were also low. Decreases were noted in New York, North Dakota, Rhode Island and the District of Columbia.

Pinning down the reasons that rates have increased so widely isn't easy. Some blame a more sexualized culture and greater acceptance of births to unmarried women. Others say abstinence-only sex education and a possible de-emphasis on birth control may play a part. And just where abortion fits into the puzzle won't be known until late this year or early in 2010, when 2006 abortion data will become available from the New York City-based Guttmacher Institute, a nonprofit that has been tracking abortions since 1974. Government abortion statistics are based on voluntary state reports and do not include every state.

Sarah Brown, CEO of the National Campaign to Prevent Teen and Unplanned Pregnancy, says she is less inclined to believe abortion is driving higher teen birth rates and suggests that increases in high-profile unmarried births in Hollywood, movies and even politics is a significant factor for impressionable teens.

"In the last couple of years, we had Jamie Lynn Spears. We had Juno and we had Bristol Palin. Those three were in 2007 and 2008 and not in 2005 to 2006, but they point to that phenomenon," she says.

The new data also reflects the first decline since 1968 in the average age of first-time mothers, dropping from 25.2 years in 2005 to 25 in 2006. Demographers attribute it to the teen birth increases.

By Sharon Jayson, USA TODAY