CHICAGO -- Republican John McCain's presidential campaign released a new television ad Tuesday that says Democratic rival Barack Obama is bad for families because he supports sex education for kindergartners.

Obama's campaign called the ad a "shameful" distortion.

The ad says Obama has a weak record on education and that his only accomplishment was legislation to teach sex education to kindergartners.

"Learning about sex before learning to read?" the ad says. "Barack Obama. Wrong on education. Wrong for your family."

But the legislation was not Obama's, it never became law and it would have required age-appropriate information in schools. Obama has said that means warning young children about sexual predators and explaining concepts like "good touch and bad touch."

"It is shameful and downright perverse for the McCain campaign to use a bill that was written to protect young children from sexual predators as a recycled and discredited political attack against a father of two young girls," Obama spokesman Bill Burton said in a statement.

Burton noted that in a recent interview with Time magazine, McCain refused to define 'honor.' "Now we know why," Burton said.

The McCain campaign released the ad hours after Obama gave a speech on education and offered proposals normally more popular with Republicans. Obama promised to double funding for charter schools, pay teachers based on performance and replace those who aren't up to the job.

As a state senator in Illinois, Obama voted for the sex education bill in committee in 2003, but he was not a sponsor.

The measure said schools offering sex education must include medically accurate information appropriate to the age of the students. The lessons were to cover the consequences of unprotected sex, the effects of various forms of contraception and the option of abstinence.

It also would have allowed parents to pull their children from sex education classes if they wished.

The full state Senate never voted on the bill.

The following year when Obama ran for the U.S. Senate, Republican Alan Keyes tried to make an issue of the sex-education vote, but it never gained traction with Illinois voters. Obama defended the idea of giving kindergarten pupils some basic information -- that babies aren't brought by a stork, for instance -- but said those decisions should be left to local school officials and parents.

McCain's ad is to air in parts of Pennsylvania, Minnesota, Iowa, Michigan, Ohio, Missouri and Wisconsin, as well as on the Discovery channel.