Scientists at Leeds University have found that VR sets could trigger eyesight and balance problems in young people unless changes are made to devices. 

Scientists studied children aged 8–12 playing 20-minute games. Researchers have warned that virtual reality headsets can cause more damage to children thakn adults.

The Association for Psychological Science in their February 2014 issue revealed that virtual avatars may impact real-world behavior

five minutes of role-play in virtual environments as either a hero or villain can easily cause people to reward or punish anonymous strangers,” 

This comes from lead researcher Gunwoo Yoon of the University of Illinois at Urbana-Champaign.

Re-consider VR headsets for your children.  They may not be worth the health risk associated with it.