Parents using new products which allow them to track their children may develop an "unhealthy and destructive" relationship with their child, a privacy group has warned.
The Japanese pioneered the use of GPS for child safety
Earlier this month, two new, low-cost devices which use Global Positioning Systems (GPS) were launched in the US, with both retailing for under $50. One is a miniature mobile phone, the other is built into a shoe.
And entertainment giant Disney is planning a mobile phone, targeted at up to 30 million children, which uses GPS to monitor where they are.
But Simon Davis, director of campaign group Privacy International, told BBC World Service's Culture Shock programme that he feared parents using GPS would find it both ineffective and dangerous.
"What this can result in - and we've seen this through visual surveillance technology and bugs that can be put into children's bedrooms - is parents becoming obsessed, to the point of having an unhealthy and destructive relationship with their children," he said.
"There is, particularly for young teenagers, a very important space that needs to be nurtured, for the development of the adolescent psyche.
"Parents have to be careful not to intrude too closely on that neutral zone."
There is a growing fear throughout the West about the safety of children, and parents are increasingly feeling they need to know where their children are and what they are doing.
The trend for using GPS for tracking children began in Japan, with school backpacks and blazers being fitted with transmitters. These were hooked up to a monitoring headquarters at a security firm.
But Mr Davis said that if parents can track their children, "people with sinister intent can do so too".
"There is no such thing as a secure system," he added.
The Galileo project launched Europe's own version of GPS
Mr Davis, who is also a visiting professor at the London School of Economics, said that one of his students had successfully proved how easy it was to hijack a GPS system, by putting Mr Davis' phone on a tracking project without his knowing.
It was done, he explained, by the student sending the phone a junk text message from a British-based website. Mr Davis said he deleted the text without realising its significance, and for 30 days afterwards, the students tracked his movements.
"When we get to GPS tracking, that process goes beyond the cells we have at the moment, to tracking to within a few metres," he said.
"If students can do that to me, then somebody who wants to do harm to a child can do it very simply.
"Parents should be outraged about the commercial availability of that service, rather than spending hard-earned money trying to track their own children... these companies are reinforcing fear, and falsely giving hope."
However, Michael Chong, a leading trend analysts in the US where this technology is being heavily promoted, said that he did not believe that the goal is to be tracking children.
Instead, he argued, it is giving people the "comfort" to parents of knowing that if something goes wrong, they have another method of being able to get hold of them.
He explained that similar technology had been put to highly effective and successful use by the US government, where it is designed to identify where a call to the 911 emergency system is located.
This, he said, means the emergency services can "instantly pinpoint" where someone is who needs help.
"I think that's a really great idea, because many, many times people can't even describe where they are," he added.
"I take the optimistic view. I believe technology has saved a lot of lives, and will continue to do so."