Woman who had sex with identical twins can’t know for sure who fathered her child
A UK court has ruled that a pair of identical twins who both had sexual relations with the same woman within a four-day period cannot determine which of them fathered her child.
The Court of Appeals in London said that only one brother can appear on the child’s birth certificate, but at present, it is “not possible” to identify the biological father, according to reports.
The case arose after the mother and one of the twins asked the court to grant him parental responsibility. The other twin had already been listed as the child’s father following an earlier court decision, The Guardian reported. Judges, including Sir Andrew McFarlane, noted that DNA testing confirms only that either twin could be the father, without clarifying which one.

For privacy, the mother and twins were not named, and the child is referred to as child P.
McFarlane emphasized that leaving the question of parental responsibility unresolved is not in the child’s best interest. Judge Madeleine Reardon previously explained that both brothers had sexual contact with the woman within the same four-day window of conception, making it equally plausible for either twin to be the father.

Until the case is resolved, the twin currently on the birth certificate will not have legal parental responsibility. McFarlane noted that while future scientific advances may eventually identify the biological father, achieving that now would require “very significant cost,” leaving the situation unclear for the time being.