Unless there exists a specific warrant, ordering DNA tests of all the children while in custody, the DNA of the children is inadmissable in court.
Which, is another reason to fault TX in this action - CPS did do some things right. Medical exams, vaccines, DNA tests - if you dropped a baby in my house, I would do all those things as a mater of course.
Like getting a stray dog a rabies shot, once you adopt it.
Of course, since the custody was illegal - so was the rest of it.
Why a DNA test? What purpose could it serve? If required later by a court, the test you did would not serve, probably. The same is probably true with the CPS DNA tests. In order to have any relevance whatever, the CPS would have to have taken fingerprints to accompany every DNA sample and somebody would have to testify as to the connection between the DNA and the fingerprints.
What the CPS did was an attempt to establish the details of certain suspected crimes, without having the probable cause to collect the evidence. If the CPS "evidence" DID indicate a possible crime, all the samples that were relevant would probably have to be repeated.