A woman who had sex with two twin brothers in just a few days apart is unable to identify who is the father of her child. The appeal court stated that standard DNA tests are practically useless in this case – because the brothers have practically identical genetic material.
What does the London thing say?
In London, a woman who has had relations with identical twins in just four days is unable to determine which of them is the father of her child. The appeal court ruled that DNA tests are useless because twins have identical genetic material.
In this case, the mother of the child had relations with two brothers in a short time, close to the ovulation period. When the baby was born, both men began to question who the real father was.
The standard paternity test, which in typical cases confirms paternity with a probability above 99.9%, did not decide anything here. For the test, both men are "the same" genetic father – because their DNA is almost identical.
The appeal court accepted the situation and stated that it could not clearly identify which of the brothers was the biological father of the child.
Why can twin DNA "mistake" tests?
Single-egg twins (identical) are formed from one an egg that is divided into two after fertilization. In practice, this means that their DNA is very similar – they are almost "clones".
Standard DNA tests analyze only a few dozen selected sequences that are in identical twins practically the same. For this reason, the test shows that "one of them certainly is", but does not indicate which one exactly.
Can this ever be solved technically?
Theoretically, it is possible to use a very advanced method, such as full genome sequencing, which examines practically the entire DNA helix.
Such an analysis can detect minor mutations that have arisen in each of the brothers after the separation of the cell, so that it is possible to indicate which of them is the father with a high—but not a hundred percent—probability.
The problem, however, is the cost (in one of the previous cases it affected £75–90 thousand), time and lack of guarantee of a 100% result, so it is not a realistic solution for many families.
How does this affect the law and parental responsibility?
In the British system, the appeal court did not revoke the father's name from the file because, as he pointed out, there is no evidence that a man entered on the metric "is not" the father: for there is a 50 percent probability that he is.
