Of course they don't function as gills, but five-week human embryos can be regarded as little pink fishes, with gills. - Richard Dawkins

Evidence is the only good reason to believe anything

"However statistically improbable the entity you seek to explain by invoking a designer, the designer himself has got to be at least as improbable. God is the Ultimate Boeing 747" (p. 138)

The second requirement of a virus-friendly environment – that it should obey a program of coded instructions – is again only quantitatively less true for brains than for cells or computers. We sometimes obey orders from one another, but also we sometimes don't. Nevertheless, it is a telling fact that, the world over, the vast majority of children follow the religion of their parents rather than any of the other available religions. Instructions to genuflect, to bow towards Mecca, to nod one's head rhythmically towards the wall, to shake like a maniac, to "speak in tongues" – the list of such arbitrary and pointless motor patterns offered by religion alone is extensive – are obeyed, if not slavishly, at least with some reasonably high statistical probability.