Woman's double-twin relationship sparks court's impossible paternity ruling

The child (referred to as "P"), who was conceived in 2017, is now 8 years old, according to court documents.

The U.K. woman, who was only identified as "the mother," reportedly engaged in sexual relations with the identical twins just four days apart.

The mother and the twin who is not listed on the birth certificate brought the case, seeking to overturn an earlier ruling and have him legally recognized as the child's father, the document detailed.

"Currently, the truth of P's paternity is that their father is one or other of these two identical twins, but it is not possible to say which," stated Lord Justice Moylan in the Court of Appeal ruling.

Moylan added that the child's paternity "is binary and not a single man," highlighting the legal uncertainty created by the case.

The case is significant because it ​​reveals a limit of DNA evidence, which is the foundation of many legal cases.

Monozygotic (identical) twins share virtually identical genetic profiles, including the markers used in standard paternity tests, meaning they "cannot be differentiated using standard DNA testing," according to a study published in Forensic Science International: Genetics.

A study published in PLOS Genetics confirms that distinguishing between identical twins' DNA requires highly specialized analysis that goes beyond standard forensic testing.