Law

Up to May 2012 there was no law in the UK that specifically related to regulating the use of children's biometrics. 

However in May 2012, after 7 years of campaigning, the Protection of Freedoms Act was passed with the issue of parental consent for processing childrens biometrics being contained in
Chapter 2 Protection of biometric information of children in schools etc. 
Clauses 26-28:

26. Requirement to notify and obtain consent before processing biometric information
27. Exceptions and further provision about consent and notification
28. Interpretation


The salient points of the Act are:

  • Each parent of the child should be notified by the relevant authority that they are planning to process their child's biometrics and notified that they are able to object.
  • In order for a school to process children's biometrics at least one parent must consent and no parent has withdrawn consent. This needs to be in writing.
  • The child can object to the processing of their biometrics regardless of parents consent.
This law becomes enforceable in September 2013.

Up to May 2012 the below UK laws helped clarify which area of law the taking and processing of children's biometric data without parental consent fell under the Acts of Parliament listed below UK
Data Protection Act
Human Rights Act
Education Act
Freedom of Information Act
Children Act
Gillick Competence

USA
In the United States there have been laws passed either prohibiting or regulating schools processing children's biometrics.

Arizona SB1216 - Feb 2008, prohibiting biometric data collection of pupils by schools
Illinios SB1702 - 2007, Consent using biometric technology in schools
Illinios HB1559 - School Code amended. Re: biometric consent
Illinois SB2549 - 2005/2006, Consent using biometric technology in schools
Iowa HF685 bill as it used to, see ACLU report here (original link broken but can be found here with more information here)
Michigan Opinion No. 7069