A set of twins in California were born 15 minutes apart, but their birthdays fall on different days, months and years.

Alfredo Trujillo was born on 31 December, 2021 at 11.45pm, according to the Natividad Medical Centre.

Aylin Trujillo, his twin sister, was born 15 minutes later, at exactly midnight on 1 January 2022.

According to CBS News, the mum said it’s crazy to her that they are twins and have different birthdays.

“I was surprised and happy that she arrived at midnight,” mother Fatima Madrigal said.

Aylin Trujillo was also the first baby to be born at Natividad Medical Centre in 2022, the hospital said.

“Twins with different birthdays are rare, and some estimate the chance of twins being born in different years as one in two million,” the hospital said.

CBS reports that Dr Ana Abril Arias, a family doctor at the Natividad Medical Group, said it was “definitely one of the most memorable deliveries of my career”.

The newborns have three older siblings, two girls and a boy.

Madrigal said her oldest son is so excited to have a brother, and the rest of their family is equally excited to meet them.