A slow, 30-year rise in infanticide rate, coupled with a sharp drop in teen homicides, means two groups are now being murdered at almost equal rates.  The homicide rate for Americans aged 15 to 19 was 9.6 per 100,000 in 2000, the same year that the rate for infants (children under the age of 1) peaked at a 30 year high of 9.1, twice what it was in 1970.

"Infants are the most defenseless members of our society and the most deserving of our protection.  If degree of risk is going to guide our domestic policies, then when the infant homicide rate equals the teen rate, it's time for us to pay attention," Brett Brown, study's director & databank supervisor for Child Trends.  The Child Trends study tracked the two homicide rates back to 1970, a benchmark starting point used in federal policy deliberations.

No one is sure why the infant homicide rate has steadily climbed over the past three decades.  One explanation may be better reporting.  Coroners and medical examiners, under pressure from pediatricians and others, have been receiving better training in the signs of child abuse.  Infant deaths that at one time would have been attributed to accidents or sudden infant death syndrome are increasingly being ruled homicides.  This also would help explain a corresponding decline in SIDS deaths.

Some researchers believe, that despite such advances, the reported homicide rate for infants is probably lower than the actual rate, perhaps by as much as 50%.  Coroners and physicians still misdiagnose infant deaths to an astonishing degree, said a longtime researcher at the U.S. Department of Health & Human Services who wished to remain unidentified.  If examiners are uncertain, they will label a case "pending investigation," which means it won't be counted by state or federal authorities, the researcher said.

A study of children's deaths in Colorado from 1990 to 1998, half the cases listed as accidents, or due to natural or unknown causes, on death certificates were later attributed by a review board to abuse or neglect.  The study, published in the Pediatrics Journal in August, compared death certificates to follow-up reports on the same death by state-mandated review boards.  A Washington Post investigation of child deaths in Washington, D.C. from 1993 to 1995 found similar underreporting of abuse and neglect.

Signs that an infant has been murdered are particularly difficult to recognize, researchers said.  A baby can be shaken, suffocated or drowned without causing external injuries.  Authorities also may be reluctant to question grieving relatives.  "We are too trusting and don't want to think a parent would do this," said Kent Hymel, medical director of pediatric forensic assessment at Inova Fairfax Hospital.

White parents in particular escape scrutiny, Hymel says.  In both the Colorado study and the projects he has been associated with, doctors tended to correctly attribute a child death to homicide or other forms of maltreatment more often in black families than in white ones.  While a higher proportion of infant deaths occurs in poorly educated African American families, the increase has occurred at about the same pace across racial groups and is not restricted to those who are poor, the Child Trends report shows.

"It's not just poor people who kill their kids," said Robert W. Block, chairman of pediatrics at the University of Oklahoma-Tulsa.  Block, who runs a committee on child abuse for the American Academy of Pediatrics, said stress or mental illness can trigger violent behavior.  "We see it at all levels.  Babies are easy targets when you lose it."

On the day a child is born, his or her chance of being murdered is at least 10 times greater than on any other day, experts said.  During four weeks last summer in Los Angeles County, three newborns were found dead in waste or recycling plants.  During the first week of life, an infant is most likely to be killed by its mother.  Young, unwed mothers may deny that they are pregnant, said Rosemary Chalk, senior research associate at Child Trends, and may fear that they have brought shame to their families by having a child.  In some cases, they already have young children and the thought of caring for another can push them over the edge.  "They are very isolated mom," said Chalk, usually "delivering by themselves, outside the hospital."  They also are not taking advantage of "safe haven laws" that many states now have.  The laws allow a mother to leave her child at a hospital or fire station within 72 hours of birth with no fear of prosecution.

Once an infant is more than a week old, however, the perpetrator is usually male, often a father or stepfather.  Infant boys are more likely to be murdered than infant girls.  Boys are killed more often, because they are more likely to be born prematurely and thus are more vulnerable.  Also, they are usually more fussy in the first few months of life, perhaps because of colic.  Shaking a baby, usually in an attempt to stop the crying, is the number one way infants are killed, according to the American Academy of Pediatrics.  It only takes a few seconds.

In fact, a child is at greater risk of being murdered during the first year of life than in any other year until the age of 17, when guns become more accessible.  David Finkelhor, who runs the Crimes Against Children Research Center at the University of New Hampshire, believes he knows why little attention has been paid to infant homicides. "People who kill teenagers are a threat," he says.  "The gun-toting gang member, or the child molesting abductor, is really scary to everybody.  People who kill their kids don't threaten other people.

Infant deaths involve issues that are politically troublesome, including abortion, termination of parental rights, support for unmarried teenagers.  It's hard to address these deaths without getting into those other issues.  Government agencies say they're taking a closer look at detecting and preventing infant homicides.  Child fatality review teams, like the one that operated in Colorado, are increasingly common at the state level, though they are frequently unfunded and rely on volunteers.  Criminal court judges are beginning to administer heavy sentences against convicted offenders, including life imprisonment and execution.

The Centers for Disease Control and Prevention has provided funding to five states to develop better methods of counting cases of child maltreatment.  "We're zeroing in on what is harming children, and we include within that infant homicides," says Rodney Hammond, CDC director of violence prevention.