An Indiana law that requires pornographic websites to verify users’ ages — one of numerous such statutes in effect across the country — is being challenged by an association of the adult entertainment industry.

In April, the U.S. Supreme Court rejected a request by the same group, the Free Speech Coalition, to block a similar law in Texas.

According to the Indiana law signed by Republican Gov. Eric Holcomb in March, the state’s attorney general and individuals can bring legal action against a website’s operator if material “harmful to minors” is accessible to users under the age of 18.

In addition to Indiana and Texas, similar laws have been enacted in Arkansas, Kansas, Louisiana, Mississippi, Montana, Oklahoma, Utah and Virginia. Backers of such laws say they protect children from widespread pornography online, while opponents say the laws are vague and raise privacy concerns.