It is commonly assumed by many that at the very start of the game a scenario of escaping capture is playing out and while that is true to an extent there is a much more shocking truth behind it.
For those who have discovered the alternative ending to the game where the protagonist disconnects what looks to be something related to the control helmets you should know that it is revealed that the protagonist then slumps lifelessly similar to other characters once you're done controlling them. So if the child is being controlled how is that so, what is the true nature of these controllable people we see march and follow instructions and who is the one controlling them.
I'd like to turn your attention to the pig farm we see, like in my previous interpretation blog of the game http://inside.wikia.com/wiki/User_blog:Starscream1998/My_take_on_the_story_of_Inside. I still believe it to showcase the dystopian nature of the world right now as Pigs are commonly used for medicine practice and the leeches as well show a very worrying state of affairs. The resulting diseases caused a near extinction of the human race so what could we do...recreate the human race. That is what the people being carted off in the lorry are as well as the long lines of people marching and jumping on que, the underwater children, the workers and deformed creatures who ally themselves with you throughout the game and even the very child you play as. They're not mind controlled or genetically altered, they're test tube people. They're a new labour force, a new obedient population and now that leads to other question...who controls them.
The Blob of course, the first attempt at creating new human life now used for the shared hive mind it has with the beings created out of it's flesh. It's connected to those helmets that are used for control but is seems it managed to work behind its creator's backs by controlling the protagonist to unhook it and then it recombines with the child.
The Blob is the singularity, the thing used to create this subservient race of pseudo-humans. This is the story of it's attempts to get free. The Blob controlled its children but was controlled by its creators, you could even say they're more than its children, they are literally a part of it but thanks to the efforts of the protagonist it becomes free.