I actually kind of doubt the present scientific theories about the origins of human life on this planet are correct. They're just the latest popular version. I suspect those theories will presently be replaced by other rather different theories in the halls of scientific orthodoxy. They are interesting, though...

What I think scientists mostly think about is...

Sex. Dinner. Having a drink. Peer pressure. Career advancement. Finances. Professional status. Their new car.

You know, the usual stuff... :-)

A few really brilliant ones probably think about William Shatner now and then too.