Mohammed and Aftab Asghar, who happens to be Identical twin brothers, have appeared in court charged with raping a woman as they cannot be told apart by their DNA. The twins were arrested after evidence taken from the scene linked the alleged crime to one or both of them.
Prosecutors have charged both siblings as they are unable to tell which one of the two is the suspected sex attacker.
Police and the Crown Prosecution Service were continuing their investigation to try to determine whether they should pursue the case against both men.
The 22-year-olds were expected to enter pleas when they appeared alongside each other in the dock at Reading Crown Court, Berks.
But the prosecution asked for more time as police and the Crown Prosecution Service continue their investigation to try to determine whether they should pursue the case against both men.
Prosecutor Sandra Beck said: "It is an unusual case. They are identical twins. The allegation is one of rape.
"There is further work due and there is an indication which would tend to support that one was not at the location. It may mean that only one of the defendants faces trial."
No details were revealed about the circumstances surrounding the alleged offence, which is understood to have occurred on November 5, 2011.
Ms Beck confirmed a trial date for the pair had already been set for December 2.
The twins were granted bail by Recorder Lawrence West QC.
In February this year, identical twin brothers were arrested on suspicion of a series of rapes in France.