The Times does the knowledge on New York:
Why more girls than boys enter the programs is unclear, though there are some theories. Among the most popular is the idea that young girls are favored by the standardized tests the city uses to determine admission to gifted programs, because they tend to be more verbal and socially mature at ages 4 and 5 when they sit for the hourlong exam."Girls at that age tend to study more, and the boys kind of play more," said Linda Gratta, a parent at the Anderson School on the Upper West Side, one of the most selective. "But it's a mixed bag. The day of the test, you could be the smartest boy in the world and just have a bad day." She said that Timothy, her first-grade son, had approximately 10 boys and 18 girls in his class.Biases and expectations among adults are often in play when determining which children count as gifted, and fewer boys appear to end up in gifted programs nationally. A 2002 study by the National Academy of Sciences reported that boys were "overrepresented in programs for learning disabilities, mental retardation and emotional disturbance, and slightly underrepresented in gifted programs," said Bruce A. Bracken, a professor at the College of William & Mary who wrote one of the two exams that the city uses to test gifted children. He said the implications of the study were "disturbing."Dr. Bracken's assessment, which makes up 25 percent of a child's gifted score in the city, has been field tested for gender bias, and during a recent round of testing in Virginia, no gender differences in the score were recorded. But the longer Otis-Lennon Ability Test, the other 75 percent of the gifted exam, is "more verbal than some of the other tests," which could play to girls' strengths, said David F. Lohman, a professor and testing expert at the University of Iowa.