We stem from the same human being and his wife who was given to help him. Then we have the same genes with some variation between generations. However we live in different surroundings some with evil parents that cause deep traumas in their offsprings and give them inclinations to get different mental disorders. We are sensitive in different ways because of erros in the replications of the DNA chain.. "These errors can cause mutations in the DNA sequence, which can have different effects on the organism. For example, a mutation that changes a single nucleotide can alter the amino acid sequence of a protein, affecting its function. Mutations can also disrupt regulatory regions of the DNA, leading to changes in gene expression or splicing." https://www.bing.com/search?pglt=43&q=error+in+DNA+spiral+and+mutations&cvid