When parents from distant ethnies have children together it can lead to surprising results. Rules of genetics hold that children always carry half the genes of each parent. However, when parents are from the same ethny, they have many distinctive genes in common, so their children actually carry more than half of each parent’s distinctive genes. In this sense, parents who descend from the same lineage and who share many of the same genes are more closely related to their children — in terms of the number of genes they share — than are parents who have children with someone of a distant stock.

Surprising as this may seem, if an Australian and a Mbuti were to have a child together, each parent would be more closely related genetically to everyone in his original ethny than he would be to the child. Complete strangers would be closer kin than the child, and from a strictly genetic standpoint would have a greater claim on family loyalty. Most ethnies are not as distant as aborigines and Mbuti. However, the same principles apply. Outmarriage with a member of a distant ethny produces children who are relative genetic strangers to their parents.

If 10,000 Danes were to take the place of 10,000 Englishmen it would represent a loss of genetic interests to the English who remained. Dr. Salter calculates how great the loss would be: So many English genes would disappear that it would be the equivalent of removing from the population 167 children or siblings of the native population that remained. The loss is far greater if the English are replaced by more distant ethnies. If, instead of Danes, 10,000 Bantus replaced 10,000 Englishmen, it would be the genetic equivalent of the loss of 10,854 children or siblings. As Dr. Salter explains, “Some ethnies are so different genetically that they amount to negative stores of those distinctive genes.”