Discrimination against children and youth is caused by the bias adults have for other adults that causes them to discriminate against young people. Bias for adults is called adultism. When something is based on adultism, it is called adultcentrism.While adultism is sometimes appropriate, adultcentrism is often inappropriate.
Genetic makeup refers to the genes that determine what you look like and what physical characteristics you have. They are your GENOTYPE, and when these genes are expressed (the color of your eyes, your blood type, your hair texture, the structure of your digestive enzymes, etc), you are showing your PHENOTYPE.
If a mistake happens early, then more cells will have the DNA change but still not all of them. To work, the genetic test is going to have to sequence a lot of DNA to find the few base pair difference between the twins. Not only that, but the police will need to know what tissue the DNA comes from so they can compare it to the right tissue in the twins.