LONDON, (AFP) – They were born within minutes of each other, but the British twins celebrating their first birthday yesterday are far from identical: one of the girls is black while the other is white with blond hair and blue eyes.

Through a genetic quirk, Millie Biggs is dark-skinned like her Jamaican father while her twin sister Marcia has a fair complexion and strawberry blonde hair, the Birmingham Evening Mail reported on their first birthday.

“People have said that it’s one of those unusual things to do with the genes. It’s very rare that it happens – a one in a million chance,” the girls’ mother Amanda told the paper.

Millie and Marcia, who were conceived after Amanda underwent in vitro fertilisation treatment, “looked alike when they were born,” their mother said.

“We never knew how different they were going to look,” she said.

“Their different appearance settled down after a few months, but it means that Millie now looks like her dad, with black hair and dark skin, and Marcia takes after me, with fair skin and strawberry blonde hair,” she added.