Yes, the human brain does suck at multi-tasking. I think women just do more of it than men and so get marginally better at it.
When you are raising children, taking care of the house and, possibly, working all at the same time, you HAVE to multi-task. If you don't, life falls apart!
Give somebody something impossible to do, yet make it mandatory to do it, and people will figure out how to get it done!