Beyond the ads-SDK certification, apps directed at children face broader restrictions: no behavioral advertising to kids, tighter limits on data collection, age-appropriate content only, and permissions requests scoped to what's strictly necessary.
A common cause is a kids' app requesting a permission (like precise location or contacts) that isn't essential to its core function, which draws extra scrutiny under the Families program's stricter permission bar.
"Your app is designated for children but requests a permission or collects data not essential to its core functionality, in violation of the Designed for Families program requirements."