Here's why:
* Gen comes from the Greek word "genos," meaning "birth" or "origin."
* Genesis refers to the beginning or origin of something, especially the creation of the universe as described in the Bible.
* The -esis suffix is a Greek suffix that signifies "action" or "state of being."
So, the base "gen" carries the core meaning of "birth" or "origin," and the suffix "-esis" adds the concept of "action" or "state of being," resulting in the complete meaning of "the act of creation" or "the beginning."