The children all have gastroschisis, a defect where the bowel protrudes through an opening in the abdomen wall.
The mothers of the children all lived in Waterdales, in Northfleet, Kent, when they fell pregnant.
More than a coincidence: Mothers (from left) Stella Coffee, Natalie Margetson and Juliet Green with Ms Margetson's son Leon (sitting left) and Ms Green's daughter Courtney, who were both born with gastroschisis
A sixth mother’s unborn child was also diagnosed when she was living in nearby Dover Road. The cases stretch over a period of 12 years.
The group discovered the unusual similarity after chatting with neighbours, family and friends. Now they want answers.
Sonia Dalton, 35, said her daughter Mikka, now aged three, was diagnosed during her 21-week pregnancy scan.
GASTROSCHISIS: ITS CAUSES, DETECTION AND TREATMENT
Gastroschisis is a congenital defect in the abdominal wall, almost always to the right of the navel, through which the abdominal contents freely protrude.
It is more frequent in male babies than female.
Pregnancies that involve infection or a maternal age lower than 20 increase the risk of the condition developing.
Smoking, drug abuse and any other factor that contributes to low birth weight can be a factor.
A recent study has made a link between gastroschisis and having children with different fathers, suggesting that the immune system of the mother may play a part.
It can also be inherited.
Successful pre-natal diagnosis means expecting mothers can be referred to a specialist, and a caesarean section or induced natural birth can be performed before term - to allow for immediate surgery.
Advanced surgical techniques and intensive care means that mortality rates have fallen to ten per cent in cases.
Mikka was in intensive care for five weeks after she was born and has had her bowels, appendix, ovaries and fallopian tubes put back into place.
She visits King’s College Hospital, London, every six months for check-ups and takes daily medication.
Ms Dalton said: 'I told the doctors about the other cases and they were gobsmacked - we need answers to this.'
Juliet Green, 39, was living in Waterdales when her unborn daughter Courtney was diagnosed.
Now aged 10, Courtney has had multiple operations, including two blood transfusions a year, in one of the worst cases of gastroschisis.
Ms Green said: 'It seems so weird that this has happened to so many people living in the same street. We haven’t been given a reason why, we just don’t know.'
Ms Green said she was stunned when her elder daughter Natalie Margetson, who still lives in Waterdales, said her unborn child had also been diagnosed.
She said: 'She phoned me up crying and I thought she’d had a miscarriage. We want to see if other parents have had problems and see if anything can be done.'
Unassuming stree: Waterdales, in Northfleet, Kent, where five cases of gastroschisis have been diagnosed. A sixth case was diagnosed in nearby Dover Road
Her daughter Natalie, 21, said: 'I was pregnant with Leon at the same time as Sonia [Dalton], so to hear both our children had gastroschisis was a shock.'
The most recent cases are those of expectant mothers Stella Coffee, 38, and Chantelle Stevens, 23, who have also been told their babies will be born with the condition.
Ms Coffee said: 'I came back from the scan and told my neighbour, who said I was the fifth such woman. I couldn’t believe it.
IMPOSSIBLE ODDS OF WATERDALES
Gastroschisis is a condition that affects one baby in every 10,000 births.
Although the incidence of the condition is on the rise in the UK and in other countries, the concentration of cases in one area is highly unusual.
Dr Mark Kirby, professor of maternal and foetal medicine at the University of Birmingham, said gastroschisis was associated with a low maternal age - the ratio among mothers under 20 rises to 4.71 per 10,000, compared with 0.26 per 10,000 in mothers aged between 30 and 34.
That makes Waterdales even more unusual, as Ms Green was 29 and Ms Dalton 32 when they had their babies, and expecting mother Ms Coffee is 38.
But a concentration of the condition is not unprecedented.
Shiela Brown, chief executive of the Newlife Foundation for Disabled Children, said a significant number of women in south Wales with gastroschisis babies in 1995 prompted a national summit of leading clinicians and researchers.
'It is quite traumatising. No one wants to see their baby hurting. We’re lucky in some ways that there are many of us and we’re not going through this on our own.'
A sixth child was born with gastroschisis in a nearby road.
Helen Gallagher, 35, now lives in the neighbouring town of Higham but lived in nearby Dover Road in Northfleet 12 years ago when her son Lewis was born with the condition.
The group has been advised by doctors at King’s College Hospital to report their cases to the Director of Public Health at NHS Kent and Medway for a full investigation.
A spokesman for King’s College said the hospital could not comment on individual cases.
The women have the backing of Gravesham MP Adam Holloway, who said research showed bowel dysfunction could be caused by mothers living close to where pesticides had been used.
He said: “I think a public health investigation would be a very good idea, and I am writing to the Secretary of State for Health along these lines.'
A spokesman for Gravesham Council, the local authority, said it had not been informed yet by any public health bodies of the cases.
Sheila Brown OBE, chief executive of the Newlife Foundation for Disabled Children, said: 'Gastroschisis is believed to be the fastest growing inborn condition in the UK and incidences are also increasing in other countries.
'This is a departure from current trends, as child health is generally improving.'