The rapid adoption of the crops is evidence that American farmers see the technology as beneficial.

Critics of biotechnology, who say the crops may be risky to health and the environment, have issued studies saying that use of the crops has resulted in increased reliance on pesticides and has had only a minimal effect on crop yields.

The National Research Council report, more than 200 pages, was prepared by a committee of mainly academic scientists, and it relied primarily on peer-reviewed papers.

Still, the report is not likely to win over critics of the crops.

One critic, Charles Benbrook, said the conclusion that the crops help farmers might not be true in the future. That is because the report relies mostly on data from the first few years, before prices of the biotech seeds rose sharply and the glyphosate-resistant weeds proliferated.

Image A Missouri corn and soybean farmer with a sample of BioTech seed corn. Credit... Dave Kaup/Reuters

“This is a very different future,” said Dr. Benbrook, an agricultural economist who is chief scientist at the Organic Center, which promotes organic food and farming. “The cost is going to be way higher. The environmental impacts are going to go up fairly dramatically.”

As prices of the biotech seeds have risen sharply, even some farmers are now starting to question whether they are worth it. Just last week, Monsanto, the leading agricultural biotechnology company, said it would lower the prices of its newest genetically engineered soybeans and corn seeds because farmers were not buying as many as it had expected.

The Justice Department is investigating whether Monsanto, which has patents on the Roundup Ready system, is violating antitrust laws, unduly increasing prices or hindering innovation.