One in a million chance: Twins, one white one black
These births are so rare, genetics experts estimate them at one in a million.
Although there have been reports of twins born one white and one black in the last decade, some of these children still have trouble convincing people that they are related.
Today, Lucy and Maria Aylmer from Gloucester, England made the news when they shared their story of how they have to produce their birth certificates to strangers to prove they are twins.
The Daily Mail reported that these 18-year-old babes, born to a half Jamaican mum and Caucasian dad said that even their mum was shocked when she first saw them.
Said Lucy: "Things like skin colour doesn't show up on scans before birth. So my mum had no idea that we were so different. When the midwife handed both of us to her, she was just speechless.
"Most twins look like two peas in a pod – but we couldn’t look more different if we tried. We don’t look like we have the same parents, let alone having been born at the same time.
"Maria was outgoing whilst I was the shy one. But Maria loves telling people at college that she has a white twin – and I’m very proud of having a black twin."
The twins have three older siblings, two brothers and a sister whose skin colour is in between theirs.
Apart from their difference in skin colour, their hair and eye colours are also different - Lucy has straight ginger-coloured hair while Maria has darker hair with curls; Lucy has blue eyes and Maria's are brown.
Skin colour is believed to be determined by up to seven different genes working together.
If a parent is of mixed race, their eggs or sperm will contain a mixture of genetic codes for both black and white skin.
However, if both the egg and sperm contain all white genes, the baby will be white. And if both contain just the versions necessary for black skin, the baby will be black.
Watch this other family who beat the odds and actually produced two sets of these rare twins:
Source: Daily Mail, YouTube