A Texas judge on Friday blocked the state’s upcoming ban on gender-affirming medical care for minors, the latest in a legal fight over efforts by conservatives to restrict such care around the country.

The decision came on the same day a Missouri judge ruled that a similar law can take effect.

A group of families and doctors sued to block the Texas law, arguing it would violate parents’ rights and have devastating consequences for transgender children and teens who would be denied treatment recommended by their physicians and parents.

The ruling landed just ahead of the 1 September start date for the ban. The Texas attorney general’s office was expected to quickly file an appeal to let the law take effect.

In Missouri, the ruling by the St Louis circuit judge Steven Ohmer meant that beginning next week, healthcare providers are prohibited from providing gender-affirming surgeries to children. Minors who began puberty blockers or hormones before Monday will be allowed to continue on those medications, but other minors won’t have access to those drugs.

Some adults will also lose access to gender-affirming care. Medicaid no longer will cover treatments for adults, and the state will not provide those surgeries to prisoners.

Physicians who violate the law face having their licenses revoked and being sued by patients. The law makes it easier for former patients to sue, giving them 15 years to go to court and promising at least $500,000 in damages if they succeed.

The ACLU of Missouri, Lambda Legal and Bryan Cave Leighton Paisner last month sued to overturn the law on behalf of doctors, LGBTQ+ organizations and three families of transgender minors, arguing that it is discriminatory. They asked that the law be temporarily blocked as the court challenge against it plays out. The next hearing in the case is scheduled for 22 September.

But Ohmer wrote that the plaintiffs’ arguments were “unpersuasive and not likely to succeed”.

“The science and medical evidence is conflicting and unclear,” Ohmer’s ruling said. “Accordingly, the evidence raises more questions than answers. As a result, it has not clearly been shown with sufficient possibility of success on the merits to justify the grant of a preliminary injunction.”

The law expires in August 2027.

Proponents of the law argued gender-affirming medical treatments are unsafe and untested.

Every major medical organization in the US, including the American Medical Association, has opposed bans on gender-affirming care for minors and supported the medical care for youth when administered appropriately. Lawsuits have been filed in several states where bans have been enacted this year, and the president of the regional Planned Parenthood has pledged to “work with patients to get the care they need in Missouri, or, in Illinois, where gender-affirming care is protected under state law”.

The Food and Drug Administration approved puberty blockers 30 years ago to treat children with precocious puberty – a condition that causes sexual development to begin much earlier than usual. Sex hormones – synthetic forms of estrogen and testosterone – were approved decades ago to treat hormone disorders and for birth control.

The FDA has not approved the medications specifically to treat gender-questioning youth. But they have been used for many years for that purpose “off label”, a common and accepted practice for many medical conditions. Doctors who treat trans patients say those decades of use are proof the treatments are not experimental.