Teen girls who have low iron are more than twice as likely to score below average in mathematics achievement tests than similar girls with normal iron status -- even if they have no signs of anemia. The lower the iron, the lower the scores, according to information presented at the 2000 combined annual meeting of the Pediatric Academic Societies and the American Academy of Pediatrics in Boston. Iron deficiency is common among infants and toddlers, but not in children ages 6 through 11. When girls begin menstruating, though, they lose iron at the same time that they are growing rapidly and need more iron. Teen girls have sometimes been observed to be less interested in math than boys are. Perhaps some of this stems from iron deficiency.