Children's fingerprints will not be used by the bad guys because the children have no full capacity for behavior, and the method of using fingerprints is nothing more than criminals leaving others' fingerprints at the crime scene after committing crimes, or being falsely used by others to sign contracts. These are all things that children's fingerprints can't do.

Fingerprint, also known as handprint, refers to the mastoid pattern on the palm skin of the first finger in a narrow sense. It can increase the friction when the hand touches the object, which makes it easier to exert force and grasp the object. Fingerprints in a broad sense include fingerprints, knuckles, palm prints, foot prints and foot palm prints. There are three basic shapes of thread-bucket, bow and dustpan. Because the fingerprint repetition rate is very small, it is called "human ID card".