There have been countless people who have looked at their life and wondered why they are here, but religions do not always answer that question. Many of them cite the origin of the physical world, and they then move on to how it was peopled by a deity. What they do not adequate explain is why the deity created them in the first place. There are few writings that give a definitive answer on this subject.
People have children for many different reasons, and many of those who believe in a religion have substituted those reasons for an explanation as to why any powerful being would create the race of man. When it comes to any actual writings on the origin of religions, mankind is still searching for them for something that will tell them the real reason behind their creation. It could have been the same as those drives that still continue to populate the modern world, or it could have been nothing more than an experiment by a deity with the power to create.