This story has been updated.

Arkansas lawmakers voted by a simple majority Tuesday to override Gov. Asa Hutchinson’s veto of a ban on gender-affirming medical care for youth. The bill penalizes doctors for treating youth diagnosed with gender dysphoria, the condition in which a person’s internal sense of gender doesn’t align with their sex assigned at birth. 

Advocates call the bill, which is the first of its kind to pass, the most extreme anti-trans measure passed this year. The ACLU has vowed to sue over the measure.

“This bill will drive families, doctors and businesses out of the state and send a terrible and heartbreaking message to the transgender young people who are watching in fear,” said Chase Stangio, deputy director for transgender justice with the ACLU, in a statement. “Gender-affirming care is life-saving care and banning that care will have devastating and in some cases deadly consequences.”

Hutchinson had vetoed House Bill 1570 after a public pressure campaign from LGBTQ+ advocacy organizations just hours before the bill was set to become law. 

“Bill 1570 would put the state as the definitive oracle of medical care, overriding parents, patients and healthcare experts,” Hutchinson said at a press conference on Monday. “While in some instances, the state must act to protect life, the state should not presume to jump into the middle of every medical, human and ethical issue.” 

Hutchinson added that the state wanted to send a message of “tolerance and diversity.” Hutchinson, who due to term limits cannot run for governor again, penned a transgender sports ban into law in March. 

Major medical associations, including the American Medical Association, have agreed that transgender children can be prescribed puberty blockers to temporarily pause development until they are old enough to decide if they want to medically transition. 

But the lives of transgender kids have become a hot-button issue this year, as Republican state lawmakers have introduced more than 90 anti-trans bills, most of them aimed at preventing transgender girls from playing sports or accessing transgender-affirming medical care. 

The ACLU criticized Arkansas’ bill as among the most extreme of those proposed measures, arguing that such care has been shown to reduce suicidality in transgender youth. 

“This bill flies in the face of common decency, basic human rights, and the advice of every major medical association — not to mention federal law,” said Holly Dickson, ACLU of Arkansas executive director, in a statement. “What could possibly be more cruel than trying to take away a child’s access to the care that could save their life?” 

States passing anti-trans laws have historically faced fierce economic backlash. Last week South Dakota Gov. Kristi Noem vetoed that state’s anti-trans sports bill, citing fears that it would lead to a lawsuit. Noem, however, issued an executive order to the same effect.