Claim: Barack Obama created a bill to teach comprehensive sex education to kindergarteners
Truth: Obama supported a bill that would have provided funding to teach young children how to avoid being sexually molested by adults

In what has widely been considered one of the lowest points in the history of political campaign commercials, John McCain's campaign recently released this advertisement:

There are multiple errors in this short advertisement. Obama did have other achievements related to education while in the Illinois legislature, but most notably, the bill in no way supported "comprehensive sex education" for kindergarteners. The only education in the bill aimed at children that young was to help them recognize inappropriate touching, or other signs that an adult might be about to molest or abduct them.

“I have a 6-year-old daughter and a 3-year-old daughter, and one of the things my wife and I talked to our daughter about is the possibility of somebody touching them inappropriately, and what that might mean,” Mr. Obama said in 2004. “And that was included specifically in the law, so that kindergarteners are able to exercise some possible protection against abuse, because I have family members as well as friends who suffered abuse at that age.”
It is a misstatement of the bill’s purpose, therefore, to maintain, as the McCain campaign advertisement does, that Mr. Obama favored conventional sex education as a policy for 5-year-olds. Under the Illinois proposal, “medically accurate” education about more complicated topics, including intercourse, contraception and homosexuality, would have been reserved for older students in higher grades.

NY Times - Ad on Sex Education Distorts Obama Policy