Judge Michael Holbrook of the Franklin County Court of Common Pleas said that the two transgender children and their families who are suing to challenge the law, which would also prevent transgender girls from competing on girls' sports teams, would be permanently harmed if the law takes effect on April 24.
The order will remain in place for two weeks, or until a hearing on the families' motion for a longer-term order blocking the law.
Ohio is one of at least 22 Republican-controlled states that have passed laws restricting gender-affirming care. Tuesday's ruling comes a day after the U.S. Supreme Court allowed Idaho to enforce its ban while it appeals a lower court order blocking it.
Holbrook said the families were likely to succeed in their argument that the Ohio law improperly addressed two separate subjects, healthcare and sports, rather than a single subject as required by the Ohio constitution.
He did not directly address whether they were likely to succeed in proving that the law was discriminatory and took away families' right to make choices about their healthcare.
"We are thrilled and relieved that Ohio's ban on gender-affirming healthcare has been halted and that transgender youth can continue, for the near term at least, to access medically necessary healthcare," Freda Levenson of the American Civil Liberties Union of Ohio, a lawyer for the plaintiffs, said in a statement.
A spokesperson for Ohio Attorney General Dave Yost, who is defending the law, declined to comment.
Ohio's Republican-controlled legislature passed the law in January.
The vote overrode the veto of Governor Mike DeWine, a Republican who said he made his decision after hearing from parents of transgender youth that gender-affirming care had been lifesaving for their children.
(Reporting by Brendan Pierson in New York; Editing by Bill Berkrot)
By Brendan Pierson
