British and American children are among the worst off in the industrialized world, according to a U.N. report Wednesday that ranked the well-being of youngsters in the two countries at the bottom of 21 wealthy nations.

The report from UNICEF put the Netherlands in first place; the United States and Britain came in 20th and 21st overall, both countries falling in the bottom third of five of the six categories measured.

The British government immediately criticized the report, saying it used years-old data that did not measure recent improvements on issues such as teen pregnancies.

Among the report's overall findings was that wealth alone did not guarantee a high ranking, with countries that lagged in income sometimes scoring ahead of richer ones.

"The Czech Republic, for example, achieves a higher overall rank for child well-being than several much wealthier countries including France, Austria, the United States and the United Kingdom," the report said.

UNICEF ranked the countries in six categories: material well-being, health and safety, education, peer and family relationships, behaviors and risks, and young people's own subjective sense of well-being.

The United States was last among the 21 nations for health and safety, measured by rates of infant mortality, low birth weight, immunization, and deaths from accidents and injuries.

Britain was last in the family and peer relationships ranking, which measured such things as the rate of single-parent families and whether families ate the main meal of the day together more than once a week.

Britain also finished at the bottom in behaviors and risks, which considered factors such as the percentage of children who ate breakfast, consumed fruit regularly, were overweight, used drugs or alcohol or were sexually active.

The United States was second last in both the family and peer, and the behaviors and risks categories.

The British government said information used in the U.N. study did not take note of recent improvements to education, living and health standards. Some of the statistics went back as far as 2000 or 2001.

"In many cases the data used is several years old and does not reflect more recent improvements such as the continuing fall in the teenage pregnancy rate or in the proportion of children living in workless households," said a spokeswoman for Department for Education and Skills, on customary condition of anonymity.

She said reforms introduced to tackle "teenage smoking, drinking, and risky sexual behavior ... are delivering improvements that are making real differences to children's lives."

Opposition Liberal Democrat lawmaker Annette Brooke said the report reflected a "shameful level of child poverty" in Britain.

"It is shocking that we are doing so badly at bringing up our children," Brooke said. "Every child should be entitled to live in a stable, loving family environment."

The Netherlands topped the combined list, placing in the top 10 for all six categories studied.

In general, European countries dominated the upper half of the table, with northern European countries — the Netherlands, Sweden, Denmark and Finland — claiming the top four places. While northern countries tended to rank higher in the report, southern European countries such as Spain and Portugal ranked higher in terms of family support and levels of trust with friends and peers.

Spain came in fifth, Germany 11th, Canada 12th and France 16th.

Marta Santos Pais, the study's director, said future reports would devote even more energy to assessing how children perceive their own well-being and needs.

"Very often we base our assessment and governments shape their policies on the basis of what adults feel the policy measures are achieving," she said. "It's always important to see how the beneficiaries of those policies are assessing the impact of the policies."