Seeking Science Fiction
1. Greg Egan's Diaspora contains very nice description of "birth" and childhood of post-human person;
2. The whole Hyperion series (including endymion) has parasites;
3. Life Artificial: "birth" and life of an AI: http://lifeartificial.com/
4. Lives of Tao: https://www.goodreads.com/book/show/15981711-the-lives-of-tao
5. Orson Scott Card: Ender series books 3 and 4.
6. Robert Charles Wilson: Spin series (parasites are parasiting/symbioting on the civilisation rather than individual)