History is often wrong. Yes, we've taken for guarantee of the African Theory so far, but as more modern science develop and more people are joining the science of archeology, more places are being excavated, we're seeing things which questions the theory. Recently a finding in Europe (IDA) and few weeks ago, another finding in the Middle East shows some concerns about the original theory. While these cases might not be sufficient to challenge the old school of the African origin, but it is definitely a thing to consider. We could we completly wrong about something. Take a look at IDA, 47 million years old, and LUCI that modern world hails is only 3+ million years old.. If you can, find the documentary and watch it complety, it's an eye opening and definitely questions whether we really started out from Africa.
http://www.revealingthelink.com/