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.

The city’s Department of Education mandated the use of the two tests for admission to gifted programs beginning in 2008; before that, individual schools and districts each devised its own criteria. These typically included a mix of standardized intelligence tests, interviews, observation and, for later grades, class work. The additional leeway in admissions sometimes led to an effort to create gender balance in classes.

“Up until about five years ago, there was more of a conscious effort to balance by gender,” said Estelle Schmones, who retired last year as a gifted teacher at Public School 110 in Manhattan. Like other educators and parents, Ms. Schmones noted that the number of girls in some gifted programs had been creeping up over the past several years.

David Cantor, the press secretary for the Education Department, said that any role the tests might play in contributing to the gender gap was not known, because the city did not tally the gender of those who took or passed the test, only those who enrolled in gifted classes. Still, Mr. Cantor said, “A good test for giftedness should be able to control for differences in what children have been exposed to, and for the early verbal development we see more often in girls.”

Image Educators and experts have long known that boys lag behind girls in measures like high school graduation rates and college enrollment, but they are concerned that the disparity is also turning up at the very beginning of the school experience. Credit... Katie Orlinsky for The New York Times

The imbalance stands in contrast with the gender makeup of the eight high schools, including Stuyvesant High School, the Bronx High School of Science and Brooklyn Technical High School, that use the Specialized High Schools Admissions Test to select students. All have more boys than girls, in keeping with research that shows that boys tend to catch up with girls, especially in mathematics, through middle school and, at the high end of the achievement spectrum, surpass them. (La Guardia High School, the prestigious school for music, art and the performing arts, has three girls for every boy.)

Whatever might be keeping young boys from entering gifted programs at equal rates might also be what can cause stumbles once they get in. For some of the boys, “their social and emotional development is not at the same level as their intellectual development,” said Donna Taylor, the principal of the Brooklyn School of Inquiry. She estimated that she spent about half her day helping her kindergarten and first-grade boys as they ran into trouble with issues like collaboration, self-control and sharing.