DNA testing for wrongful convictions having been recently discussed, the following site is submitted as one that may be of interest:

www.innocenceproject.org

Some 24,000 children and juveniles in Britain have been obliged to give DNA samples before it was decided to make any case against them:these were cases of clear innocence e.g of mistaken identity, or of there being no evidence sufficient to charge, and the like.
It turns out that these samples have been kept and shall be kept permanently.[Our age of criminal responsibility is 10 years ] When an MP protested about such a case in his constituency the cabinet minister concerned said that there was nothing wrong in what had happened ! He added, helpfully, that such samples could prove someone's innocence in years to come
As if, if a man was wrongly accused, he would not have given a sample on his arrest then (he would, under present law )

So protests that this procedure was building up a data bank by stealth and was an infringement of liberty came to naught.

Still, it is only a matter of time before all British citizens will have given biometric data (for passports and i.d. cards ) and it seems inevitable that complete national DNA records will follow. So we should all be able to "prove our innocence" in advance !

For the life of me I cannot see that a means of identifying someone is unjust.

If some of these children are kidnapped, it may help the parents identify them if they are later found.

I cannot see that DNA is intrinsically worse than a passport, fingerprints, or any other method, used by most states to identify people.

If the notion is that DNA collection will convict the innocent, then I have to say that since it is a more reliable identifier than, say, a driver's licence, which can be forged, DNA identity is more likely to exonerate the innocent and convict the guilty.