DNA tests cannot be ordered to prove ‘bald allegations’ of infidelity : 

rules the Hon’ble Delhi High Court in a recent case(W v. H and Anr. – 26.08.2016. MAT.APP.(F.C.) 17/2016 & CM No.5064/2016). In this case, the High Court also summarized the following ground-principles for ordering of DNA tests in matrimonial litigation and its interplay with Section 112 of the Evidence Act : 

• Applications for directions to the other party to appear or produce off springs or siblings for DNA testing are made by parties seeking to establish, either, the factum of the relationship, or, their challenge to the relationship. It could be by a person claiming parentage or by a person challenging paternity of another.
• The court in an appropriate case, can direct medical examination of a party to matrimonial litigation as well, provided that the applicant seeking such examination has a “strong prima facie” case and has placed “substantial material” on the court record in support of his/her case.  (Reliance on AIR 2003 SC 3450 – Sharda v. Dharampal). Only when the court feels that the DNA test is eminently needed, should a DNA test be ordered.
• The presumption of legitimacy (Section 112 of the Evidence Act) thus cannot be disturbed by “slender” materials unless “compulsive and clinching” facts are brought to shake the presumption and call for a DNA examination. Proof of non-access is essential. Thus, the strong presumption under Section 112 of the Indian Evidence Act of legitimacy of a child born during marriage can only be rebutted by “strong, clear, satisfying and conclusive” evidence of “non-access”.((2005) 4 SCC 449 Sh. Banarasi Dass v. Mrs. Teeku Datta).
• “Access” and “non-access” mean the existence or nonexistence of opportunities for sexual intercourse; it does not mean actual “cohabitation” (Ref.: AIR 1934 PC 49, MAT.APP.(FC)No.17/2016, Karapaya Servai v. Mayandi ; (1993) 3 SCC 418:AIR 1993 SC 2295 Goutam Kundu v. State of West Bengal & Anr. – para 24)
• Conclusiveness of the presumption under Section 112 of the Indian Evidence Act, has the salutary purpose of preventing ‘bastardisation’ and, therefore, cannot be disturbed lightly and DNA tests cannot be ordered at the drop of a hat. (AIR 2010 SC 2851, Bhabani Prasad Jena v. Convenor Secretary, Orissa State Commission for Women & Anr)
• The presumption under Section 112 of the Indian Evidence Act can only be displaced by a strong preponderance of evidence, and not by a mere balance of probabilities or on the basis of slender material. The standard of proof in such cases must be of a degree in between the preponderance of probability and proof beyond reasonable doubt by way of abundant caution and has a matter of public policy (Ref.: AIR 2001 SC 2226, Kamti Devi v. Poshi Ram – para 11 & 12)
  

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The discussion in this regard would be incomplete without a brief note on Nandlal Wasudeo Badwaik v. Lata Nandlal Badwaik, (2014) 2 SCC 576, wherein SC ruled :

“Modern technology providing for possibility of proof of fact not available at time when Statute was enacted. S.112 of Evidence Act, 1872, interpreted in light of the fact that DNA tests can provide conclusive proof of paternity. The interest of justice is best served be ascertaining the truth and the court could be finished with the best available science and may not be left to bank upon presumptions, unless science has no answer to the facts in issue. When there is a conflict between conclusive proof envisaged under the law based on a presumption and proof based on scientific advancement accepted by the world community to be correct, the latter must prevail over the former.

Ed. Comment : The SC in this case seems to be holding that ‘Presumptions are the bats of law which flutter in the night, but vanish in the sunshine of actual facts. So construed, when real facts are known – there is no reason a presumption should prevail.’ 

However, the judgement in Nandlal (supra) should not be construed as opposite or contrary to the judgment of the Hon’ble Delhi High Court or other previous Supreme Court judgments, discussed above and has to be harmoniously read. This judgment has also been dealt with and discussed by the Hon’ble High Court in the case under discussion (W v. H – supra), in the following words :-

164. “In Nandlal Wasudeo Badwaik, the husband had led evidence that after his wife left the matrimonial home, she did not return and that he had no access to her when the child could have been begotten. The courts below had not given any finding with regard to this plea. It is also noteworthy that in this case, the DNA testing was done under orders of the court which had not been opposed by the wife. The DNA test report suggested that the appellant was not the biological father. In these circumstances, the court held in para 17 that where there was evidence to the contrary, the presumption under Section 112 of the Indian Evidence Act, being rebuttable, would yield to conclusive proof. In para 19, the court noted that the husband’s plea, that he had no access to the wife when the child was begotten, stood proved by the DNA test report.”

165. Principles laid down in prior judgments including AIR 1934 PC 49, Karapaya Servai v. Mayandi; AIR 1954 SC 176, Chilukuri Venkateswarlu v. Chilukuri Venkatanarayan; AIR 1993 SC 2295, Goutam Kundu v. State of West Bengal & Anr.; AIR 2001 SC 2226, Kamti Devi v. Poshi Ram; AIR 2003 SC 3450, Sharda v. Dharmpal and AIR 2010 SC 2851, Bhabani Prasad Jena v. Convenor Secretary, Orissa State Commission for Women & Anr. have not been overturned and bind the present consideration. 

It is worth noting that in Nandlal (supra) too – husband had led evidence to prove seperation and ‘non access’, and in that background the DNA test was ordered and its report accepted. Therefore, the net result that comes out after a discussion of these judgments is that even for ordering a DNA test – strong and clear material as to ‘non access’ is required. DNA (though scientifically accurate), by itself, cannot supercede the conclusivity of Section 112 of the Evidence Act, and cannot be furthered as the exclusive proof of ‘non access’ without other circumstantial evidence probablising non-access. This appears to be the preponderating judicial view.  This is a nuanced legal issue and students for a better understanding may go through the judgment in W v. H – http://lobis.nic.in/ddir/dhc/GMI/judgement/26-08-2016/GMI26082016MATFC172016.pdf