Power
You hold the tools to life itself. It's hard to believe men and women ever made babies without you. For example, you know if a woman will be a mother before she does. You know the gender of the baby before the parents do. You will make life-or-death decisions in not one, but two heartbeats.
You have a hand in the growth of a family's tree. You get to witness the moment when two people suddenly understand the gravity of their new jobs as parents, and you get to see the first light in a baby's eyes. You'll also be the one to deliver bad news at the worst possible time, and you'll have to be professional and intimately compassionate at the same time.
You may not be the star of the show, but you have the best seat in the house.
And if you really want to play God, wait for a baby about to be born on the cusp of two astrological signs. You could make the difference between a Taurus and a Gemini if you time it right.