Americans may never agree on the abortion issue. But one thing remains clear: Fewer women are having them, a trend that has persisted through Democratic and Republican administrations, divisive election campaigns and the underlying culture wars.
A report this month from the U.S. Centers for Disease Control and Prevention shows the trend in stark numbers: Between 1990 and 2004, the estimated abortion rate declined by 24 percent. In no single year did the rate even inch upward.
"It's been dropping since the late '80s, especially for teenagers but for all age groups too," said Stephanie J. Ventura, head of the reproductive statistics branch at the CDC's National Center for Health Statistics.
The rate fell 55 percent among girls 15 to 17; 44 percent among those 18 and 19; 30 percent among women 20 to 24 and 12 percent among women 25 to 29. Abortions among women in their 30s and 40s fell by smaller percentages.
Meanwhile, the number of abortions declined 390,000 over the time period to 1.22 million in 2004.
With abortions on the wane, it's tempting to look for a corresponding increase in the live births across America. But the birth rate fell 6 percent across the same span of time, leading experts and adversaries to search for other explanations.
The answers are probably many: more contraceptive choices, state laws requiring parental notification where minors are concerned, fewer unintended pregnancies and some surprising trends among teenagers.
It may come as a jolt to anyone who believes the worst about teenagers, but rates of teen pregnancy, births and abortions declined steadily. Preliminary data show a slight uptick in teen births in 2006, though experts say it's too early to know if that represents a true reversal.
The teen birth rate fell by 35 percent from its 1991 peak through 2005 before rebounding 3 percent in 2006. At the same time, the pregnancy rate declined by 38 percent through 2004 and the abortion rate by half.
Much has been written about a teen "hookup culture" in which casual sex has become more commonplace than ever. It may bring little comfort to parents, but demographer Joyce C. Abma said the depiction may be true for oral sex but not for the kind of sex that results in pregnancy.
In a 2002 study of sexual behavior, the federal agency found that 47 percent of teenagers 15 to 19 years of age identified themselves as "sexually experienced" - down from 51 percent in 1995. Over that period, the pregnancy rate among sexually experienced teenagers declined 17 percent.
"The other important piece is contraceptive use," said Abma of the National Center for Health Statistics. "Even in the more recent period, from the mid-'90s through the early 2000s, we saw significant improvements in contraceptive use among teens.
"That involves the barrier methods - the condom in particular - as well as the pill and the newer injectables," she said.
The 2002 study also found that the rate of both unintended and intended pregnancies declined for more than a decade. "So what that means," said Abma, "is that one didn't go up at the expense of the other. Teenagers want fewer pregnancies than they did in the past."
Stanley K. Henshaw, a consultant for the Alan Guttmacher Institute, doubts that parental consent and notification laws had much effect on the overall abortion rate. For one thing, the laws apply only to girls under 18 - a group that historically has accounted for a small portion of abortions.
"The effect is maybe minuscule, not enough to show up in these statistics," said Henshaw, a co-author of the CDC report. "And the decline [in abortions] has been across the board ... in states without restrictions as well as states with restrictions."
But Michael New, a professor of political science at the University of Alabama, argues that parental consent and notification laws deserve more credit than they're often given.
"We see the largest and most consistent declines in teen [abortion] rates in the states that have been most active in passing pro-life legislation," said New, who wrote an article on the subject last year for the conservative Heritage Foundation.
By 2006, some 26 states required parental consent or notification for a teen abortion. Maryland law requires notification - though not consent - of a parent or guardian.
The federal government gets its abortion totals from the Guttmacher Institute, which surveys providers in all 50 states. To gain a picture of trends within age and racial groups, the government uses data reported to the CDC by 46 states (including Maryland), the District of Columbia and New York City.
Maryland appears to be bucking the national trend of declining abortions. Here, abortions rose 8 percent between 2000 and 2005, a period in which the national rate declined by 9 percent.
John Nugent, chief executive officer of Planned Parenthood of Maryland, can't explain the disparity but says the availability of medical abortions may be one reason.
"The biggest trend we're seeing is women opting for more medical abortions as opposed to surgical abortions," he said. The drug RU486 received government approval in 2000 for termination of pregnancies up to 49 days of gestation.
Planned Parenthood is performing more abortions than ever, but largely to compensate for clinics that closed their doors in recent years, he said. The organization offered abortion services two days a week until 2001, when it expanded to six days.
Planned Parenthood also offers sex education in schools throughout Maryland, emphasizing abstinence as the best way to prevent pregnancies but explaining contraception as well for teenagers who decide to have sex.
Contraception options have increased over the past two decades. Pharmaceutical companies have reintroduced IUDs (intrauterine devices) and contraceptive sponges, and have marketed patches and morning-after pills that also prevent pregnancies.
It remains to be seen whether the recent increase in teen births will prove lasting, and whether it has been accompanied by a rise in teen pregnancies and abortions. The CDC has yet to publish pregnancy and abortion data for 2005 and 2006, but the preliminary birth rates have sparked concern.
"Any attempts to explain the uptick in teen births have to be regarded as pure speculation," said Lawrence Finer, director of domestic research for the Guttmacher Institute.
It's possible, he said, that the increase stems from the growing number of school districts that teach abstinence but not contraception in health classes.
That trend is not being felt in Maryland, where Baltimore County high school students, for instance, are taught and tested about an array of birth control methods including condoms, IUDS, oral contraception - and just saying no.