The twins, born 15 minutes apart in the US state of California, celebrated their birthdays in two different years, one in 2021 and the other in 2022.
According to the French news agency AFP, Alfredo Antonio Trujillo was born in Salinas at 11:45 on New Year's Eve.
Fifteen minutes later, on New Year's Day, his sister, Alan Yolanda Trujillo, was born.The Nativad Medical Center, where the babies were born, said in a statement last week that some estimates put the twins at one in two million years.
The children's mother, Fatima Madrigal, said in a statement: "It is insane to me that they are twins and their birthdays are different."
Dr. Anna Abril Arias called the baby deliveries "one of the most memorable deliveries of her career."
"It's a pleasure to help these little ones get here safely in 2021 and 2022."
Older brother Alfredo weighed six pounds and an ounce, while little Allen weighed five pounds and 14 ounces.
The Centers for Disease Control and Prevention says about 120,000 twins are born in the United States each year.