Right, just like all other diseases. If any disease had a genetic origin, it would be wiped out within a few generations.<p>Oh, except for all of these: <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;List_of_genetic_disorders" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;List_of_genetic_disorders</a><p>There are even lots of diseases that provide strange benefits that protect the sufferer from other illnesses. Having half the genes for sickle-cell trait will give you strong resistance to malaria. Having both is a terrible illness. Huntington&#x27;s Disease seems to provide resistance to certain types of cancers, but when you turn 35 or 40 your life becomes a real nightmare.<p>The point is that the purpose of genetics is not to promote healthy humans, it&#x27;s to promote the reproduction of the group of genes in question. Genes will use all kinds of tricky methods to duplicate themselves, including all kinds of things that are awful for the person with them.