How to Change "Made For Kids" YouTube Video Setting
If you make YouTube videos, you can to comply with the new law (COPPA) that makes it a requirement to tell YouTube if your videos are made for kids.
There is a new section in the upload tab that makes it easy to do this when you upload a video.
But what about all your previous videos you've already uploaded?
You can easily change that channel wide, so all your videos get the update.
If you want to change it on an individual video, you can select that video under the videos tab and edit that setting individually.
Here is the video from YouTube explaining the entire process and reasoning for this change.
And here is more information from Google's help page.