The Court assessed the case under Article 8 ECHR (right to respect for private life). The Court held that the situation indeed fell within the scope of that provision, since (para. 29):
Establishment of paternity of the applicant’s daughter is a matter related to the “private life” of the applicant, who bears full responsibility for her minor child. Recognition of the natural father, apart from its financial and emotional purposes, may also be important from the point of view of the applicant’s social image, her family medical history and the web of entwined rights and duties between the biological mother, biological father and the child concerned.After this broad and nicely worded assessment, the Court indicated the importance of the DNA test as a piece of evidence in this case (para. 34):
The Court does not lose sight of the fact that today a DNA test is the only scientific method of determining accurately the paternity of the child in question; and its probative value substantially outweighs any other evidence presented by the parties to prove or disprove the fact of an intimate relationship. Furthermore, the applicant suggested that she and the defendant had concealed their relationship; hence the genetic examination could have been the only persuasive evidence of the disputed paternity.Finally, the Court noted that a clear answer on the issue of paternity was also in the best interests of the child. By both declaring the first DNA test inadmissible and not ordering a second one. the domestic authorities had failed to strike a fair balance between the competing interests of the parties (note that no broader societal interest was at stake here), "with due regard to the best interests of the child".
For further references to other paternity cases dealt with udner Article 8 ECHR, I refer the reader to para. 28 of the judgment and to p. 147 ff. of Alastair Mowbray's 2004 book entitled 'The development of positive obligations under the European Convention on Human Rights by the European Court of Human Rights'.