(CNN)A set of California twins born 15 minutes apart are already distinguishing themselves with different birthdays.
Big brother Alfredo Antonio Trujillo was born on New Year's Eve while his sister, Aylin Yolanda Trujillo, made her debut on January 1 at exactly midnight, according to Natividad Medical Center in Monterey County.
According to the hospital, twins born in different years is about a one in two million chance.
"It's crazy to me that they are twins and have different birthdays," said the twins' mother, Fatima Madrigal. "I was surprised and happy that she arrived at midnight."
Aylin weighed in at 5 pounds, 14 ounces while big bro tipped the scales at 6 pounds, 1 ounce, according to the hospital.
"This was definitely one of the most memorable deliveries of my career," said Dr. Ana Abril Arias, a family doctor at Natividad Medical Group and faculty at Natividad. "It was an absolute pleasure to help these little ones arrive here safely in 2021 and 2022. What an amazing way to start the New Year!"
Alfredo and Aylin will join three older siblings who are very excited to meet the twins.