Prince William is "alarmed" about the impact technology is having on young people.
Prince William and Duchess Catherine
The 35-year-old royal believes we have reached a "moment of reckoning with the very nature of childhood in our society" when it comes to social media sites like Facebook and Twitter and other technology on how they affect the children of the world.
Speaking at the Children's Global Media Summit in Manchester, north England, he said: "It is the gradual nature of this change - the slow warming of the water in the pot if you like - that I believe has led us to a moment of reckoning with the very nature of childhood in our society.
"I believe strongly in the positive power of technology; but I am afraid that I find this situation alarming. My alarm does not come from childhood immersion in technology per se. My alarm comes from the fact that so many parents feel they are having to make up the rules as they go along.
"We have put the most powerful information technology in human history into the hands of our children - yet we do not yet understand its impact on adults, let alone the very young."
It comes after Prince William's brother Harry urged young people to "look up from their phones" and go out and "change the world".
He said: "The thousands of you gathered here are proof that today's generation of young people is the most connected, most energised, and most confident the planet has ever known. You know that differences of opinion, of circumstance, of race and religion - are to be respected and celebrated.
"You know that in a clickbait culture, we cannot waste time sharing and drawing attention to things that make us angry, or that we know to be false. You all know that it's great to 'like' things on social media, but that it's more important to look up from our phones, to get out into our communities, and to take real action; to stand up for what you believe in."
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