You were born because you wanted to be born and into the specific conditions and time period you chose in advance. You were born because you wanted to be here.
The reason why you were born has to do with your intrinsic desires and things you wanted to accomplish in this lifetime.
You did not come into existence at birth. You existed first in an inner unlimited dimension and decided to come to this dimension. You wanted to be born in a specific time period and location, with the parents you chose for learning purposes and because you have known them before.