This week, I am trekking 500 miles to go celebrate the 21st birthday of my twin cousins, Christie and Jacob. I couldn’t imagine missing such an auspicious occasion. Pretty much everyone I know has first cousins at the very least, but my relationship with mine is special and different. On July 19, 1995, my cousins were born from the same womb that I was. My mother was their surrogate, and after nine months of protectively housing them, she helped to give me two of my favorite humans.

When I was a little girl, I found out that my aunt and uncle couldn’t have children. I was very young at the time, but they seemed happy to play with me and be the best godparents in the world. They never seemed like they needed children because they always looked content to me. But seeing the situation from the other side of 25, I know they must have gotten lonely and sad at times, even if it never showed. These two were meant to be parents.

My uncle is my mother’s brother. My aunt is one of her best friends from before she married into my family. Before you make an assumption or call us hillbillies, nothing weird happened here. My cousins are biologically my cousins—there is not a drop of sibling blood involved. A year after my brother was born, my mother agreed to carry three fertilized eggs for my aunt and uncle because my aunt’s womb was an inhospitable environment. Nine months later, my extended family was blessed with Jacob and Christie, and I got to go to Disney World shortly after.

What I learned from this experience, and all of the years since, is that family is everything. While my mom suffered through a summer of a giant belly and swollen ankles, I spent most of my time with my aunt. She may not carry my genes, but she is blood in my eyes. She made up games for my neighborhood best friend and me to play, and she was the best at hide-and-seek. She talked to me about my future cousins in a way that made sense. She picked me up from school sometimes and tucked me into bed. I remember that it was difficult and confusing to spend half of my time away from my mom, but my aunt always made it fun. I looked forward to seeing her. To this day, I still do.

I also learned what it meant to be a sister. In the years since this event, I have seen my mother and my uncle do immeasurably kind things for one another, no questions asked. While blood and family forever bond them, as is the way with all siblings, it’s more than that. They choose to be important to each other. They choose to make time and be close, and that is a lesson I have carried into my relationship with my own brother. I know that if the same situation were to occur, I would never hesitate to devote nine months of my life to help him, and vice versa. Being a good sister is one of the most important jobs in my world, and I would never trade that for anything.

Most importantly, I got my cousins. I never saw them as siblings, but they have always been more to me than sideline family members. I got to watch them be born into this world, and hold their tiny bodies in my little arms. I watched them learn about the world around them, and teach them the things I already knew. I went to their middle school graduation, helped Jacob write his college essay, and listened to Christie cry on the phone to me when things went wrong. I am unbelievably blessed that they were brought into the world by somewhat unconventional means, and I can’t picture what my life would have been had that not happened.

I am proud to be part of my family, and to tell this story. I am proud of the fact that I have not only my own parents to turn to, but my godparents as well. I am proud of my kind, genuine cousins, and the amazing people they have become. In a world where one in 10 woman cannot start a family, I am proud that my family found an amazing exception to the rule. I am grateful for modern medicine, strong bonds, and 21st birthdays at the beach with two of the best kids to ever exist.