"I would also point out that gorillas and humans do not share a common ancestor, whereas chimpanzees, whom also do not have a saggital crest, do share a common ancestor with humans." Not true. All apes share a common ancestor, as do all primates, all mammals... and indeed all life on earth does. Chimpanzees are indeed our closest relatives, that is the species with whom our common ancestor is most recent. Unless of course god created the earth after the divergence of gorillas and humans/chimps but before the divergence of humans and chimps.