Parallel Universe

What if there were such a thing as a parallel universe?   How would things be different in that place?  I would surmise that mostly things would be the same as there would have to be a fundamental difference in humanity to not arrive at the same inventions in a similar time frame and fashion…. What may be the main difference is simply choices that have been made by humans.  The wheel would still be invented but Org may choose to mate with Blug instead of Erg as it happened in our universe….  All it would take is one person to do something different in their universe than what they did in ours and humanity in both universes would go in completely different directions.   Just something to think about…..