Former PSV Eindhoven chairman Harry van Raaij has urged teenage fullback Jetro Willems to reject any offer from Manchester United that comes his way.
The left-back is being followed by United this season.
"We now see English clubs taking away players as young as 12 years of age," he said.
"It would be best if they were prevented from signing players younger than 17. For Willems, it would be a pity. It would slow his development.
"If he lives up to his potential, he would be better served staying with PSV another three years."