Both Apert syndrome mutations are distributed in testes as clusters rather than uniformly ([26], [27] and this paper) and, together with other results [22], [38], [58]–[61], support the idea that the unexpectedly high frequency of the two Apert nucleotide substitution mutations and paternal age effect results from a selective advantage acquired by mutated SrAp cells over wild type cells. The gene discussed is SRA1; the disease is Apert syndrome.