Financial analyst Catherine Howarth, 35, who is of Nigerian heritage, believed the rare recessive white gene that resulted in son Jonah, three, being completely white would not strike a second time, Daily Mail Online reports.
So she was stunned when the midwife handed her daughter Sophia and she was as white as her big brother.
The mum from Milton Keynes, Bucks, believes she is the only black mother in the world to have given birth to two white, blue-eyed children.
She said: ‘When Jonah was born, a genetic specialist said he was a one-in-a-million baby. He said it was extraordinary with my African background that I’d had a child with blue eyes and pale skin.
‘He calculated the possibility of it happening again was less than one in a million.
‘So when Sophia was born with white skin and blue eyes I was more than taken back with shock. It seems the odds of it happening twice are millions-to-one. No-one has heard of a black mum having two white babies one after the other.’
While husband Richard, 37, an engineer, is completely white, the couple from Milton Keynes, Buckinghamshire thought their second child would be much darker than their first.
Catherine said: ‘When I had Jonah he was so white both Richard and I thought the midwife had given us the wrong child. But if anything, having Sophia has been even more of a shock because we were sure it couldn’t happen twice.
‘I was stunned when I saw her blue eyes and light skin.’
Doctors were equally amazed when Sophia was born last March.
She adds: ‘Each time doctors and midwives have all commented on our babies’ amazing coloring. People often get confused when they meet me with the children for the first time.
‘You can see them doing a double take, wondering if I am their mum. I do get tired of being stopped in the street by people asking if I’m the nanny. People seem to find it hard to understand how I could give birth twice to white children.
‘But when people get to know us more, they often say despite their blue eyes and white skin, they can also see a lot of my characteristics.’
Catherine is of Nigerian decent with no white genes in her family.
‘My parents were from Nigeria and as far back as anyone can recall my family have all been black.
‘The only explanation seems to be there must have been a white gene in my family that has remained dormant for years until now. And now it seems to be very dominant.’
Despite the initial shock, the couple are delighted with their miracle children.
When Jonah was born, his stunning looks attracted the attention of five modelling agencies.
His little sister, ten months, is now set to follow in his footsteps as she has already been signed up to talent agencies. At just three weeks she landed her first modelling job.
Dad Richard said: ‘While it is interesting how the genes have aligned themselves, it doesn’t matter to us what color our children’s skin is. We just feel incredibly lucky to have a beautiful son and daughter. Having healthy and happy kids is all that matters.’
Colleen Lynch, a Molecular Geneticist at Care Fertility said: ‘While you might imagine this couple would have babies who are a mixture of both their skin tones, there are so many genes involved that it is a million-to-one chance they have had white babies.
‘It is likely there is a white gene somewhere in the woman’s remote ancestry and due to an evolutionary throwback – known as atavism – this trait has suddenly reappeared.’
Meanwhile, Prof Ian Jackson from the MRC Human Genetics Unit at the University of Edinburgh said if the couple go on to have more children they could also be white.
‘Once such a couple get together, the chances of any of their children having pale skin would be one in four or even one in two.’