The district's proposal follows "national sexuality education standards" and also would address sexual orientation and bullying for the first time, FoxNews.com reported Thursday.
Under the proposal, students in kindergarten through third grade would learn about appropriate and inappropriate touching and feelings, the district said. In the fourth grade, students would learn about puberty and HIV, the virus that causes AIDS.
From fifth grade and beyond, instruction would include discussions on reproduction, contraception, and the transmission and prevention of HIV/AIDS, the district said.
"It is important that we provide students of all ages with accurate and appropriate information so they can make healthy choices in regards to their social interactions, behaviors, and relationships," Chicago Public Schools Chief Executive Officer Barbara Byrd-Bennett said in a statement.
"I just don't think it's appropriate," Melissa Diebold, a parent, told MyFoxChicago.com. "I don't think its age appropriate. They have no concept of anything like that at that stage in life."
Parents can elect not to have their children participate, the district said.
If approved, the program would be implemented by 2016.