I read a sci-fi/thriller novel many years ago, probably published between 1980-1990 in the USA in English that had the following elements:
- A feral child/teen is found in the wilderness, but his brain is underdeveloped.
- Scientists "fix" him with a brain tissue transplant to increase his intelligence.
- The child rapidly develops vast intelligence, surpassing his doctors.
- The doctors hire a prostitute to do an experiment on the teen/experiment
- Teen develops telepathy
- Teen uses super brain to augment another low-intelligence female patient.
- The book ends with the end of the world and the teen and his newly-enhanced female friend watch the end of the world from a jungle. There is a definite Adam/Eve vibe to the ending.
- Protagonist may be named Adam.