Lo Prohibido (La Saga de los Ancestros 1)

Set 40,000 years ago, in humanity's dark and forgotten past, Rebaa never imagined she would be fleeing for her life across the Nine Gods Mountains, her lover dead, her tribe massacred, and a ruthless chieftain on her every step. And she never imagined the ferocity with which she would fight to protect her child, a boy who should never have been born. In an age where different human species live separate and hostile lives, Rebaa has committed the ultimate transgression. Her own people would destroy her child without hesitation. The Neanderthals would demand her death. Even those who could help her harbor painful secrets that could turn them against her in an instant. But Rebaa will endure hunger, predators, and brutal enemies before she will give up her child. Because what grows inside her is not just forbidden. It is far more dangerous than anyone can imagine.