Oklahoma's highest court on Tuesday struck down a law imposing restrictions on abortion providers, including a requirement that they take samples of fetal tissue from patients younger than 14 and preserve them for state investigators.

The law also set new criminal penalties for providers who violate abortion-related statutes as well as individuals who help a minor evade the requirement to obtain parental consent. In addition, the bill created a new, stricter inspection system for abortion clinics.

Legislators had said the fetal tissue section was aimed at capturing child rapists and that the law would protect women's health. But the New York-based Center for Reproductive Rights, which challenged the law in court, said it unfairly targeted facilities that perform abortions.

In a unanimous opinion, the nine-member Oklahoma Supreme Court found the law violated the state constitution's requirement that each legislative bill must address only "one subject."

The rule, the court said, is designed to prevent legislators from including provisions that would not normally pass in otherwise popular bills. The state unsuccessfully asserted that each part of the law addressed a single subject: women's reproductive health.

"We reject defendants' arguments and find this legislation violates the single subject rule as each of these sections is so unrelated and misleading that a legislator voting on this matter could have been left with an unpalatable all-or-nothing choice," Justice Joseph Watt wrote for the court.

In a concurring opinion, four judges said they also would have struck down the law as an unconstitutional burden on a woman's right to have an abortion.

Lincoln Ferguson, a spokesman for the Oklahoma Attorney General's Office, called the decision "disappointing."

"This law would have given law enforcement the ability to more easily prosecute sexual assaults of children that are discovered when a child under 14 has an abortion," he said.

"The Attorney General's Office remains committed to defending laws aimed at protecting the safety and well-being of Oklahoma women."

In a statement, Center for Reproductive Rights President Nancy Northup said the law was "nothing but a cynical attack on women's health and rights by unjustly targeting their trusted health care providers."

Oklahoma's Republican-dominated government has joined several socially conservative states in enacting abortion restrictions in recent years, drawing court challenges.

In June, the U.S. Supreme Court struck down a Texas law imposing strict regulations on facilities that perform abortions. A similar law is on hold in Oklahoma while the state Supreme Court considers its legality.