The Supreme Court is hearing arguments in a free speech fight over California's attempt to regulate anti-abortion crisis pregnancy centers.

The case being argued Tuesday involves information required by a state law that the centers must provide clients about the availability of contraception, abortion and pre-natal care, at little or no cost. Centers that are unlicensed also must post a sign that says so.

The centers say that they are being forced to deliver a message with which they disagree because their aim is to steer women away from abortion.

California and abortions rights group that backed the law say its goal is to provide accurate information about the range of options facing a pregnant woman.

The outcome also could affect laws in other states that seek to regulate doctors' speech.

In Louisiana, Texas and Wisconsin, doctors must display a sonogram and describe the fetus to most pregnant women considering an abortion, according to the Guttmacher Institute, which supports abortion rights. Similar laws have been blocked in Kentucky, North Carolina and Oklahoma.

Doctors' speech has also been an issue in non-abortion cases. A federal appeals court struck down parts of a 2011 Florida law that sought to prohibit doctors from talking about gun safety with their patients. Under the law, doctors faced fines and the possible loss of their medical licenses for discussing guns with patients.

In another lawsuit over regulating crisis pregnancy centers, a federal appeals court in New York struck down parts of a New York City ordinance, although it upheld the requirement for unlicensed centers to say that they lack a license.

The abortion-rights group NARAL Pro-Choice California was a prime sponsor of the California law. NARAL contends that the centers mislead women about their options and try to pressure them to forgo abortion. Estimates of the number of crisis pregnancy centers in the U.S. run from 2,500 to more than 4,000, compared with fewer than 1,500 abortion providers, women's rights groups said in a Supreme Court filing.

California's law was challenged by the National Institute of Family and Life Advocates, an organization with ties to 1,500 pregnancy centers nationwide and 140 in California.