I think steven has a brilliant mind and he has over 30 yrs of experience dealing with physics so he knows what he's talking about. For all we know, we all are just normal beings, while hawking is above the normal. As a matter of fact, the theory on gravity creating life is truly amazing. From what i've learned, without gravity there would be no life forms except microorganisms because everything will be floating up such as lava, sand, water, and all of these are the necessary things that gives life a strong foundation. Without gravity, there would be no oxygen and life form would die due to lack of oxygen. Trees breathe in co2 and breathe out o2. See there is a theory in which hawkings idea can be base on.
This theory is the basic fundamental of evolution. This theory is also known as genetic implantation or messing with dna. For an easier understanding of these terms it would be known as breeding.
For example. When two life form meets. they date and have sex. Then the offspring carries both of the parents genes and the child becomes 1 generation smarter, bigger, skillful wise than his parents. Okay now, what if the parents had five sons and they all were normal, but after 5 tries of trying to have a child with a IQ, the parents finally gave birth to a son and as he got older. His IQ is higher than all his brothers. He will be more likely to be sucessful and wealthier than his brothers. His kids will be more likely to be smarter than his older brother's kids. This is simply the theory of Darwin's evolution. The strong only survives so they will have to evolve. In this case, only the brother with the high IQ was able to be successful and rich.
This theory is very simple. If you want bigger muscles in the family than marry a girl whose family are big and muscular and your chance of a muscular son will increase.