Texas Gov. Greg Abbott has signed into law banning gender-affirming care for most minors in the state, making Texas the largest US to place restrictions on transgender youth’s access to critical care.

Texas became the largest state in the United States to ban gender-affirming care for minors after Republican Gov. Greg Abbott signed a bill into law on Friday.

Senate Bill 14, which takes effect on September 1, bars healthcare providers from prescribing hormones or puberty-blocking medication to those under 18 in Texas or performing surgeries to help with their gender transition.

The law makes minor exceptions for youths that have begun receiving hormones or puberty blockers before June 1, 2023, and those that have attended 12 or more sessions of mental health counseling or psychotherapy over a period of at least six months before they began treatment. But it requires that they be gradually taken off them “in a manner that is safe and medically appropriate”.

Healthcare providers who are convicted of violating the law are at risk of losing their licences.

With Abbott’s signature, Texas joins 18 other states that have banned medication and surgical gender-affirming care for transgender minors, according to the Movement Advancement Project, which tracks state laws affecting the LGBTQ community. Arizona bans gender-affirming surgery but not medication like hormones.

Republicans throughout the country have railed against the use of gender-affirming care for minors, especially in the past year, arguing it could cause irreversible effects at an age when they are too young to decide.

Abbott, who has taken a strong stance against gender-affirming care, issued an order last year that states that medical treatment of transgender minors should be investigated as child abuse. However, a judge has blocked some of Texas’ investigations.

Medical associations have emphasised that gender-affirming care is warranted for adults and children who are experiencing gender dysphoria. Advocates have also argued that the bans only harm transgender youth.

The American Civil Liberties Union, the American Civil Liberties Union of Texas, Lambda Legal, and Transgender Law Center vowed last month to file a legal challenge if Abbott signed the bill to block the ban from going into effect.