OAKLAND -- Anti-abortion ads sponsored by the Oakland Roman Catholic Diocese posted in BART stations and placed on trains have stirred up a free speech controversy with many of the signs being vandalized.

BART officials say they had no choice but to post the ads -- with the line: "Abortion: Have we gone too far?'' -- after the diocese paid $43,200 to the agency because of the free-speech provisions of the First Amendment.

"We're not in the business of censorship," said BART spokesman Linton Johnson. "It is not up to a government official to determine whose opinion is right and whose is wrong.''

Many BART riders agreed during Friday's commute.

"I think it's free speech and I'm pro-choice," BART commuter Heather Williams told KTVU Friday morning. "They have the right to put the ads up and have their viewpoint out there."

But the ads -- with 280 posted on BART cars and 48 larger versions in stations -- have enraged freedom of choice advocates.

"I think every woman has noticed them,'' Suzanne "Sam" Joi, a member of Code Pink, a social justice and anti-war group, told the San Francisco Chronicle. "I couldn't believe BART would allow something like this. Why are they doing this?''

Johnson said as of Thursday the agency has gotten 29 complaints about the ads which are scheduled to run until the end of the month. Meanwhile, the political Web site indybay.org was urging activists to call BART to complain.

While the complaints have not bothered officials, the vandalism has. Hundreds of the ads have been defaced with graffiti and stickers. Others have been ripped or torn down.

"The defacement has taken to religious epithets, profanity, everything you can think of,'' Monika Rodman, coordinator of the group that placed the ads told the Chronicle.

BART said it would catch the vandals since trains are equipped with video cameras and are patrolled by transit police.