There is no specific provision in the Spanish legal system to expressly regulate DNA analysis as a means of proof in criminal trials. Given the lack of regulation for the kind of expert assessment in Spain, it is necessary to obtain the passive subject's informed consent, that is, it is necessary that the subject be willing to give the samples on which DNA tests will be carried out. There is no obligation in the Spanish legal system to undergo these kinds of tests. There are no special regulations applying to specific groups of people. Spain was one of the few remaining European countries not to have legislated the use of the techniques in criminal evidence, despite experts' view that regulation was needed, in view of the repercussions for the fundamental rights of the individuals concerned.