AT ODDS of more than 500 million-to-one, proud parents Jane and Barry Gregory will be celebrating their good luck in having two sets of twins by marking their children’s 13th birthday on the 13th of January.

Becky and Norman Gregory will be celebrating their 13th birthday on Tuesday, January 13.

Helping them cut the cake and open cards will be their older siblings, Patrick and Beth, who reach their 14th birthday on Sunday, February 8.

Mum Jane, 40, and dad Barry, 41, of Winchester Road, Claremont, decided to mark the occasion because for a short time they will all be 13 together.

Jane, an advertising sales rep in Manchester, said: "I believe they are the only sets of twins in the north west who were born within such a short time of each other.

"At one point, they held the national title, until someone down south had twins 10 months apart.

"The unique thing about my four is that they are both boy/girl sets, which I’ve been told is a 500 million to one chance of happening.

"We decided to mark the occasion when they are all 13 together, and will do the same for other special occasions such as their 18th and 21st birthdays."

Jane describes the shock of learning that she was going to give birth to two sets of twins.

On the first occasion, she had taken time out from studying for a degree in European studies and languages at Manchester Metropolitan University and was initially stunned when told she was expecting twins.

She said: "There was a history of twins in my family - my great-grandfather’s first wife had two sets of twins, but neither set survived.

"When she died, he remarried and his second wife had twins who did survive.

"I was a bit scared when the radiologist told me my first pregnancy involved twins and it was hectic coping.

"I took time out from my studies and had planned to go back after the birth, but got pregnant by mistake.

"When the same radiologist told me I was having twins again, I went hysterical and they had to get a nurse in to calm me down.

"I really don’t know how Barry and I coped at first - and I suspect we wouldn’t have done without the help of social services who provided vital home care.

"And thanks must also go to my mum who took on all four babies when I went back to work after five months.

"But despite all the hard work, we are so proud of all four of them - they were worth all the hassle."