Fascinating subject matter. What follows is just an idea of what may have happened....
...in a forested valley, in what is now Italy...=/-40,000 years ago...
Kuti was unhappy. He wanted to mate, but the clan had rejected him. Every time he approached a female in his clan they yelled at him and threw rocks to discourage him. The men didn't like him either. On the last two hunts his spear had not only missed, it had hit Dirok, the son of the Leader. Dirok had lived, but now walked slowly and breathed loudly. The Leader had hit Kuti's head so hard he now couldn't hear on that side. He ate last, even after the old ones and small girls.
Today Kuti was wandering through the forest, in hopes of finding some food. He had found a few berries, but not enough for his growling belly and certainly not enough to take back to the clan.
His sense of frustration grew. On the ground was a rock and he picked it up and threw it with a an anguished grunt. To his surprise he heard a scream. Scrambling through the brush he found one of the Others. His rock had hit her on the leg, leaving it cut and bruised.
But Kuti didn't concern himself with that. This Other was a female and not going anywhere. She was ugly, as the Others were. Big forehead, short bushy hair, stocky. The females in Kuti's clan were slender and had long flowing hair which he liked. Now though, he felt the urge to mate. Roughly he pushed the Other female back and mated her. At first she screamed, but then quieted down. After he was done he looked at her leg. He motioned for her to stay and went to find some moss. Gently he ground the moss in his hand and rubbed where his stone had hit her.
"Kuti" he said, pointing to himself.
"Kuuii" she repeated back. "Taa" she hit herself in the chest gently.
Kuti met with Taa twice more, and then she disappeared.
Nine moons later Taa woke up with pain in her belly. Grunting and screaming, she gave birth to a child. This child was different and her clan rejected both her and the child. They survived in the forest for awhile, then Taa died of starvation. The child cried and yelled, but Taa didn't move and she cried for a long time. She finally crawled to the rock where they had slept, and fell asleep, never waking up again.