During the embryonic/prenatal development of an individual, cells are constantly being made and destroyed within the uterus. We generate about three times as many neurons as we eventually end up with at birth (Developmental Biology, 2010).
By the time I was born, more of me had died than survived. It was no wonder I cannot remember; during that time I went through brain after brain for nine months, finally contriving the one model that could be human, equipped for language. — Lewis Thomas (1992), a physician and a poet.
