Through iterated gene editing of stem cells and the (sometimes unethical) mass gathering of phenotypic gene expression data, scientists gradually developed the capability to create children with highly customized genomes. Due to their growing understanding of human epistasis and epigenetics, subsequent generations of humans became increasingly immune to disease and resistant to infection, with finely-tuned immune systems. With lifespans reaching into the hundreds of years and exponentially improved g-factors equivalent to modern-day IQ scores well over 200, this created a stark hereditary inequality between those who could afford such treatments for their children and those who could not.