Of course it needs a cause. Scientific theory is currently favoured towards the theory of "abiogenesis" which is the random and circumstantial creation of life under the incredibly improbable concoction of the right chemical and environmental factors that it supposedly requires.
However despite life being found throughout every corner and crevice of the world, science still isn't sure what exactly life is. We can carbon copy a cell in a laboratory and despite it being physically exactly the same, it is not alive and we are incapable of making it live. So what exactly is life?
Until we can understand what life really is, what gives what would normally be a concoction of inanimate matter the "spark" that makes it live, we will be no closer to answering the greater questions.
As if the creation of life wasn't specific and unlikely enough - it's worth considering what makes life evolve. Evolution is even more improbable and specific in its nature - evolution causes life to adapt, develop traits depending on its environment in order to survive and flourish. The nature of life and evolution are incredibly, some would say divinely, specific. In my opinion it would be extremely naive and ignorant to dismiss this as an inevitability of a massive universe like so much of science theorises it to be.
Hang on, just because science can't explain some things, yet, the only other option must be we were created by an intelligent being?
Indeed. Same point as on another recent thread - absence of an explanation (so far) is not evidence for the supernatural.
Thousands of years ago mankind believed the sun was a god. The fact we hadn't yet explained what it was did not make them right.