It is well known that identical twins have the same DNA.
However, this does not mean that they are biologically identical. From birth, identical twins have different fingerprints and navels.
As they grow older, their bodies also produce independent changes, such as body odor. The Czech Republic used the German Shepherd to distinguish identical twins, and each dog can be successfully identified.
To this end, the scientists concluded that the identical twins have different body odors.
This may be caused by the acquired environment, such as infections that change their body odor.