I enjoy reading Sitchin's books and give him credit for being one of the best and most readable experts on ancient civilizations and biblical archeology as well as understanding early language BUT...
There is one more planet in our solar system, orbiting beyond Pluto but nearing Earth periodically; Advanced "Extraterrestrials -- the Sumerians called them Anunnaki, the Bible Nefilim -- started to visit our planet some 450,000 years ago; And, some 300,000 years ago, they engaged in genetic engineering to upgrade Earth's hominids and fashion Homo sapiens, the Adam.
His absurd genetic engineering by extraterrestrials from a way past Pluto planet is contrary to common sense and contemporary genetics. The modern human genetic line traces back to 200,000 or slightly less years, it's only been the last 85,000 years that existing humans left Africa and 60,000 years that any humans settled in the fertile crescent and there's no trace of any genetic engineering in the meantime. There's never been any genetic engineering of modern humans (making all ancient astronaut fables rubbish) and definitely not in the time frame of Sumeria, Babylon or Egypt.
Why did Noah's flood happen and why was Noah and his family the only ones fit to survive?
There's a real problem with this "genetic engineering" business and that is that we would have no idea if it had happened.