The teachers do not get involved in playground talk between the kids. They also do not discuss sex or any of its results in the classroom at this age. All of this happened outside of classroom. When the kids get older, its known as "street smarts" but at this age, they call it "playground talk". And there is really no way to prevent it but there ARE ways to educate your children about topics of interest before they get the "street education" yeah? Because its GONNA happen, like it or not.
Not if you homeschool your kids its gonna happen.