A birthday is an event that is actually just a trivial point in life: the baby has already been conscious for several months, and maybe even way longer if we believe reincarnation to be based on reality. I tend to believe that the combining of mum and dad's DNA is not a two-strand but a three-strand process, with the third being the soul strand of the consciousneess of the being who chose to reincarnate at the time of birth.
And in many ways death is a similar occurence to birth: a balanced situation in one reality transforms into an upheaval, after which balance returns in a totally different reality. From womb to physical, and from physical to afterlife. Or should we call it real-life?