Vicki Schulkin, a Northern Virginia parent, knew her son Matt was bright but did not think this was a problem until some of his teachers began to bristle at the erratic working habits that sometimes accompany intellectual gifts.

“In fourth grade, his English teacher told me early in the semester that he didn’t belong in her high-level class because he wasn’t completing all of his homework,” Schulkin said. That teacher changed her mind after he showed great creativity in a poetry assignment, but other instructors were less understanding.

In fifth grade, while Matt was doing SAT math problems in his head, his math teacher refused to acknowledge that he might be gifted because he wasn’t finishing assignments that he found boring and repetitive.

At the Belin-Blank International Center for Gifted Education and Talent Development at the University of Iowa’s College of Education, this is old news. In 2004, it published an extensive report, “A Nation Deceived: How Schools Hold Back America’s Brightest Students,” with research showing that children like Matt were poorly served.

Now the center has done a follow-up, “A Nation Empowered: Evidence Trumps the Excuses Holding Back America’s Brightest Students.” Its 345 pages have encouraging stories about gifted children like Matt being allowed to accelerate their learning. But authors Susan G. Assouline, Nicholas Colangelo and Joyce VanTassel-Baska remain frustrated with school administrators and legislators impeding students who would do better in more challenging classes.

“Only nine states have policies explicitly permitting acceleration of gifted students,” they write, noting that only one state, Louisiana, prohibits it. “Sixteen states prohibit early entry to kindergarten.” Colangelo told me that the District and Maryland, Virginia and several other states let local districts set acceleration policies.

The authors list 20 forms of acceleration, including early kindergarten admission, grade skipping, Advanced Placement and International Baccalaureate and early graduation from high school or college. The research shows that many biases against acceleration, such as the fear that children will feel awkward with older classmates, are unfounded. But resistance to grade skipping still rules many schools.

Teacher training programs have not done much to alter that. “It takes more to change teacher ideas about acceleration than a weekend or week-long professional development seminar,” the authors say.

Parents who want their children accelerated have to go to great lengths to make their case. In doing so, they are called “pushy” by educators who dismiss their arguments as nonsense fed by mother love.

That was the reaction Schulkin got at her son’s elementary school. “I wasn’t even asking to have him accelerated,” she said. “I had to fight and advocate for him all the way through. It always broke my heart that there had to be kids . . . who didn’t have parents able to constantly stick up for them.”

The increasing use of AP, IB and dual enrollment in local college courses has eased the problem in high schools, but elementary and middle schools still resist moving kids ahead. The report says school counselors need to be convinced that acceleration works.

What saved Matt, Schulkin said, was a middle school that allowed more advanced students to start algebra early and the intervention of Vern Williams, a nationally known math teacher. He came to her house, confirmed that Matt had special abilities and recommended him for Thomas Jefferson High School for Science and Technology.

At 27, Matt has a successful career as a software engineer and is getting married in August. Having such a supportive parent, he probably would have gotten what he needed in any case. But the University of Iowa researchers ask a good question: Why do our schools have to make it so difficult?