Like all quadruplets, these four babies are a rare delight.

But even for quads, Amelia, Sofia, Aston and Roman are incredibly unusual – and possibly unique in the UK.

For not only were the four-month-olds conceived naturally, each came from a different egg.

Experts say they have never heard of a case of non-identical quads being conceived naturally rather than through IVF.

Their parents Katalina Martin and Matthew Davies each have a child from a previous relationship but wanted one more to complete the family.

Now, to their joy and amazement, they have an instant handful.

They thought they would be unable to have another baby after doctors diagnosed Miss Martin, 28, with polycystic ovary syndrome, which makes it difficult to conceive naturally.

But a few months later, Miss Martin discovered she was pregnant and went for a scan at Stepping Hill Hospital near her home in Stockport.

‘The sonographer was scanning me for ages and kept peering at the screen,’ Miss Martin said.

Then she was told she was expecting three or possibly four babies. ‘I just burst into tears. I didn’t take it in at first.’

Miss Martin, a hairdresser, was admitted to St Mary’s Hospital, Manchester, at 27 weeks and the quads were born by caesarean section three weeks later, in February. Sofia weighed 3lb 11oz, Roman 2lb 13oz, Aston 3lb 2oz and Amelia 3lb 7oz.

Miss Martin, who has been supported by the Helping Hands project run by the Twins and Multiple Births Association (Tamba), said: ‘I was so relieved when they were all born safe and well.

‘I couldn’t believe when I saw them lying there in their cots. They all came from a different egg… and they have different personalities.’

The odds of natural quads are about 700,000 to 1, but experts said they could not estimate the probability of a non-identical set.