Have you ever looked at your windows as a safety hazard? As an adult, you know how to behave around windows. It is not difficult to avoid falling out of one, but children don’t have the same awareness that adults do, and they could easily be hurt or even killed when falling out of a window. Because of this, you should never leave your child alone with an open window. It would also be wise to take a few precautions to make sure that a minute of distraction doesn’t give your child the opportunity to get themselves in trouble.
When opening a window, if it is possible to lower the top half of it instead of raising up the bottom half, you should choose to do the former, since it will make it harder for a child to get to the opening.
Having a sturdy bug screen can help somewhat, but these aren’t made for holding any type of weight, so they aren’t reliable for protection.
Having bushes planted below windows can also help to break the fall of a child that has somehow managed to make it out a window.