YouTube is going to ask users for an ID card or credit card if it can't determine if a user is eighteen or older and wants to watch adult videos.
The video site, part of Google, wants to check whether users are old enough to watch videos that it deems unsuitable for children.
The control system will be put into operation "in the next few months".
The measure is the result of European rules to better protect minors against harmful videos online.
YouTube restricts videos for minors in cases of violence, foul language or sexual content.
The videos can then only be viewed if the YouTube user is logged in and is eighteen years or older.
In the Netherlands, people must be sixteen or older to manage a Google account anyway.
The minimum age is lower in a number of other EU countries.
YouTube also announces that the company wants to use software more often in the long term to protect videos from minors on its own initiative.
While people "are usually the best judge of who should be able to view their content," YouTube will focus on automatic decisions.
Video makers can object if they believe that YouTube has unfairly restricted their video.