A London court has ruled that it is currently “not possible” to determine which of two identical twin brothers is the biological father of a child conceived within days of separate encounters.
According to PEOPLE, the woman became pregnant after sleeping with both identical twins within a four-day span. The woman and one of the twins later appealed a previous family court ruling after the other twin had been listed as the father on the child’s birth certificate.
They asked Court of Appeal of England and Wales to overturn that decision and grant parental responsibility to the twin not listed as the father. The court ultimately declined.
Judges Say Science Cannot Currently Distinguish Between the Twins
During the ruling, Judge Sir Andrew McFarlane explained that current testing methods could not definitively determine paternity.
“It was not possible to establish the paternity of P, other than to say that the father is one or the other of the two identical twin brothers,” McFarlane said. Because identical twins share nearly identical DNA, traditional paternity tests cannot distinguish between them.
The judge added that each twin effectively had a 50% chance of being the father.
Future Advances in Science May Provide Clarity
The court acknowledged that future scientific developments may make it possible to identify the biological father with greater precision.
“It is possible, indeed likely, that by the time P reaches maturity it may be possible for science to identify one father and exclude the other twin,” McFarlane stated. However, the judge noted that at this time such testing would involve significant cost and is not currently feasible for the case.
As a result, the court described the child’s “truth” as binary rather than linked to one specific individual.
Parental Responsibility and Child Welfare Considered
The judge also addressed concerns about how parental responsibility had been assigned.
He noted that the child’s welfare should have been carefully considered before listing one twin as the father on the birth certificate.
“With the benefit of the hindsight now achieved as to the definition of father, in my view it was wrong for the court not to achieve clarity by discharging any parental responsibility that [the twin listed as the father] may have had,” the ruling stated.






