Times Online :: Walking on all fours with the ancestors

FIVE brothers and sisters who can only walk naturally on all fours are being hailed as a unique insight into human evolution, after being found in a remote corner of rural Turkey.

[...] Some researchers claim that genetic faults have caused the siblings to regress in a form of “backward evolution”. Other scientists argue more strongly that their genes have triggered brain damage that has allowed them to develop the unique form of movement.

(Thanks for the tip, Bradley!)