AT least they will never have a problem remembering each other’s birthdays. For sisters Erin, Leah, Charlotte and Isabelle Sullivan were all born on the same date.

    The two sets of twins — the elder girls are 9 years old while the younger girls have just celebrated their first birthday — have defied odds of 4.5 million to one to arrive in the world Jan. 25.

    But despite the twins’ double-double of birthdays, the girls’ parents still face a struggle to organize everybody’s parties and gifts — as they have five other children, and another one on the way.

    It was the start of 2016 when full-time mom Zoe was rushed to from the family home in Lossiemouth, Moray, to Raigmore hospital in Inverness for an emergency C-section.

    Tiny Erin and Leah were brought into the world Jan. 25 — exactly the same date that Charlotte and Isabelle were born in 2008.

    Nursing staff were astonished by the coincidence, and the Sullivans couldn’t be happier.

    Zoe, 38, praised medical staff who cared for the premature babies in the weeks that followed their birth.

    She said, “They were fantastic. They were absolutely amazing.

    “It’s really difficult to thank someone for saving your child’s life because they just say it’s their job.”

    But she revealed they could not quite believe it when she told them how significant the date was.

    She said, “When they took me down (for the operation) I said, ‘It’s my other twin’s birthday today.’ They were like, ‘Really?’ No, really?’

    “The first time, I don’t think they really believed it. And then you say no, it really is their birthday.”

    Little Leah was tiny at 1.47 kilograms whilst her sister Erin was just 1.08 kilograms.

    But they are now thriving with Charlotte and Isabelle on hand to help look after them.

    Zoe said, “They weren’t jealous at all about sharing their birthday. They were just over the moon.

    “They went about telling everybody.

    “And then the other children were like ‘Can we have a baby on our birthday?’ But I don’t think I will be able to do that again, that was a complete fluke.”

    When it came to the first joint birthday party, military precision was required.

    Dad Ben, an engineer for the RAF, said, “It took a lot of organization. We got it set up in the evening before and they all lined up at the top of the stairs in the morning.

    “Let’s just say it took a little bit longer than usual trying to keep tabs on whose present was whose.

    “And after about 10 minutes all of the wrapping paper made it look like a recycling center.

    “We didn’t have a birthday cake — we bought them a lot of cupcakes instead because of all of the 1s and 9s.”

    The twins’ other siblings are Elizabeth, 11, Olivia, 10, Noah, 7, Evangeline, 5, and Tobias, 4.

    Statistical analysis of birth rates suggests that the odds of any conception resulting in non-identical twins is around one in 50. The odds of identical twins are higher, at one in 250.

    The odds of two births happening on the same day are one in 365, meaning that the Sullivans’ twin girls are the product of a one in 4,562,500 coincidence.

    (SD-Agencies)