This story is based on a conversation with surrogate mom Emily Westerfield, who lives in Celina, Ohio. It has been edited for length and clarity. I've carried 12 babies — some singletons, some twins.

My son Otto started preschool this fall. The previous year, during every daycare pickup, our reunion was routinely punctuated by the same questions from the other 3-year-olds in the room: Why are you ...