If natural selection has acted on the lumbar region of Homo Sapiens to create this sexual dimorphism, then this sort of trait should also be apparent in the genus Australopithecus, hominins that have been known to be habitually bipedal for at least 2 million years after the earliest bipedal hominins. Currently there are 2 nearly complete australopith lumbar segments; one has three dorsally wedged vertebrae in the lumbar region while the other has two. An explanation for these findings is that the first one is a female, while the latter is a male.