Last year, a federal judge found that a similar law in Arkansas “would cause irreparable harm” as he blocked it from being enforced. The Arkansas law, known as the “Save Adolescents From Experimentation Act,” was passed by lawmakers after overriding a veto from Gov. Asa Hutchinson, a Republican, who contended that the legislation “puts a very vulnerable population in a more difficult position.”

Still, elected officials in conservative states have pursued a range of aggressive measures this year meant not just to limit transgender youth’s access to medical care but also to penalize parents and medical professionals who are helping them transition.

In Idaho, lawmakers advanced legislation that would alter the state’s genital mutilation law to make it an offense punishable to up to life in prison to provide gender-affirming care or help a child leave the state to obtain it.

In Texas, Gov. Greg Abbott told state agencies that medical care helping a child transition should be considered abuse and investigated as such. The order had been stalled by a state court, but the Texas Supreme Court ruled on Friday that child abuse investigations over transition care could continue.

Those measures have been part of a broader effort by conservative lawmakers that critics argue is intended to marginalize the gay, lesbian, bisexual and transgender communities.

On the same day that Ms. Ivey signed the Alabama bill on medical care, she also approved legislation that requires students to use restrooms and locker rooms for the sex listed on their original birth certificates, as well as limits on classroom discussions on gender and sexual orientation — a version of what critics call a “Don’t Say Gay” measure that has been enacted by other states.

“I believe very strongly that if the Good Lord made you a boy, you are a boy, and if he made you a girl, you are a girl,” Ms. Ivey, a Republican, said in a statement after signing the bill. “We should especially protect our children from these radical, life-altering drugs and surgeries when they are at such a vulnerable stage in life.”