WASHINGTON — A highly-anticipated White House report about childhood diseases has provoked a tug-of-war pitting farmers and some prominent Republican lawmakers against health secretary Robert F. Kennedy Jr. and his “Make America Healthy Again” movement ahead of its release.

President Donald Trump promised a review within 100 days that would analyze the ramifications that U.S. lifestyle — from the medications prescribed for children to the food served on their school lunch trays — has on childhood diseases like obesity, depression or attention deficit disorder. The report, led by a so-called “MAHA Commission,” is expected to be released on Thursday.

Farmers and Republicans are nervous about what the report might say about glyphosate, the ingredient commonly used in pesticides sprayed on crops. Kennedy has denied the report will be unfavorable to farmers.

Speaking on the Senate floor on Wednesday, Iowa Republican Sen. Chuck Grassley warned that farmers have reached out to him, upset they have not been able to provide input on the MAHA report ahead of its release.

“I hope there is nothing in the MAHA report that jeopardizes the food supply or the livelihood of farmers,” Grassley said.

Last month, a group of 79 Republicans — including several senators who represent farming states — echoed similar concerns about the report saying in a letter to Kennedy that without the products agricultural “yields and quantity are negatively impacted.”

Glyphosate has been available for about 50 years and some farmers say it remains essential for controlling weeds without excessive tilling, helping to conserve both soil and fuel.

“There’s a reason why we still use: It works,” said Blake Hurst, a Missouri farmer who is past president of the Missouri Farm Bureau.

Kennedy, though, has built a sizeable following over many decades, in part, because of the lawsuits he’s waged against corporations, including the company that produced weedkiller Roundup. The World Health Organization has labeled that product’s key ingredient, glyphosate, as a probable carcinogen for humans.

On Wednesday a large group of his supporters sent Kennedy a letter calling on the commission to “hold the chemical industry” accountable in the report, noting that pressure is mounting.