Natalia Goleniowska with mum Hayley. Credit:Telegraph "All children - actually all of us - need to see every sort of person represented in the media, whether they have a disability or not," says Hayley, who writes an award-winning blog called DownsSideUp. After Frugi, Natty was in a shoot with children's clothing brand JoJo Maman Bebe, a holiday company and the local tourist attraction the Eden Project. More recently, a young boy with Down's syndrome (DS) called Seb White has appeared in M&S advertisements, and Boden employed a little girl with cerebral palsy in its recent catalogues. In Natty, Sainsbury's has certainly chosen a star-in-the-making. When we first meet, in the rose-scented gardens of the local tea rooms, she greets me with a cry that will be familiar to parents of little girls everywhere. "I'm Elsa," she announces, referencing her favourite character from the Disney film Frozen. And when I ask what she did at school today, she replies, "We did Frozen," even though her father is insisting they must have done sums or reading. But Natty is not the only one whose life has changed in the past few years. Bob and Hayley, and Natty's elder sister, Mia, 10, have all been on a steep learning curve. After giving birth to Mia in 2004, Hayley had several miscarriages before she became pregnant with Natty. At 15 weeks into her pregnancy, a scan showed that there was a 1-in-300 chance that the baby would have the extra chromosome 21 that denotes Down's.

"We chose not to have further testing,'' says Hayley. "There is a conditioning to fear Down's syndrome coupled with an assumption that if a foetus tests positive for it, you will automatically have a termination. But we were lucky to have a fantastic midwife who just reassured us we could cope, so we got on with it. Maybe we were naive or perhaps arrogantly ignorant, but we'd had Mia easily so why would the outcome of this pregnancy be any different?'' And when Natty was born in December 2006, Hayley and Bob's most urgent concern was their second child's life: following a home birth, she was born blue and silent. Later, at the Royal Cornwall Hospital in Treliske, once Natty's oxygen levels had been raised in the Neonatal Intensive Care Unit (NICU), the couple were told that their daughter did indeed have an extra chromosome. One of the common complications for children with Down's syndrome is a hole in the heart, and Natty had two, which were making it harder for oxygen to circulate around her body. "I had a flash of the stereotype - of what I thought my daughter wouldn't be able to do," says Hayley. "And I had a very real fear for her life. I knew she would need heart surgery - would I lose her? In which case, did we dare to love her? Would Bob blame me? Would he forgive me? I went into shock." Bob was more pragmatic: "I just wanted to do the best for my family, protect and support them however was necessary." For Hayley, the lightbulb moment came when a midwife warned her that Natty needed breast milk. "She bluntly said to me, 'That child needs your love now - whether she lives or dies.' It was the push I needed to get on with being a mother."

Reaction to the news of Natty's birth was muted. "People don't send cards, they don't know whether to congratulate you or not,'' says Hayley. "Someone actually said they were sorry to hear the news,'' Bob adds indignantly. "But a baby is always something to rejoice about." And, as they both point out, the diagnosis made no difference to Natty. "She was completely unaware of the stigma attached to her extra chromosome,'' says Hayley. "And when we realised that, we knew who she was - our daughter, not a set of symptoms or predictions for the future. With Mia, we could live in every precious baby moment. But with Natty we were falling into the trap of only looking ahead into the future and conjuring up problems. I'd even decided we would never be able to have a holiday abroad again." Now she shakes her head in disbelief. The family have enjoyed lots of holidays since then to exotic destinations, including Mauritius and Jamaica. Not that the early years were easy. When Natty first came home, she couldn't feed without a nasogastric tube, which passes from the nose through the oesophagus and down to the stomach, which Hayley learnt to insert as the county was short of trained nurses available for home visits. Aged two, Natty needed heart surgery to close one hole (the other had healed naturally) at Bristol Children's Hospital. Holding her in his arms while the anaesthetic took hold was terrifying, says Bob. But the results were astonishing: with oxygen circulating in her blood properly for the first time, Natty experienced a growth and development surge. To her parents' delight, they suddenly had a lively chocolate cake-devouring chatterbox on their hands. Her elder sister Mia, always protective and sensitive, gained a proper playmate, too. The two became partners in crime, swimming and playing on the beach together, riding at the local stables and of course these days acting out scenes from their favourite film, Frozen, in the garden.

For Hayley, one of her proudest days was when Natty started mainstream school at the age of five. It also left her with time on her hands - to start her blog, sharing information, ideas and positivity about life in a typical family living with Down's syndrome. Within a week, her postings about Natty were being read around the world; she now gets about 30,000 hits a month, with parents coming to share experiences or find reassurance. She has been in demand as a speaker at parenting conferences, and encouraged to campaign for wider tolerance of Down's (hence Natty's star turn for Sainsbury's), which has also seen her invited to Downing Street. When Natty was two days old, a doctor told Hayley and Bob: "You are going to be ambassadors for children like this." The couple didn't understand at first. "But now," says Hayley, "when you get an email from a family or a mum on a ward who says 'Your blog has thrown me a lifeline; now I can see what the future could hold', then we know we're doing the right thing.'' Bob adds: "Hayley has found a vocation with her campaigning.'' As for Natty, her personality could clearly take her anywhere. "Natty has a T-shirt with a quote from Hamlet on it: 'We know what we are now but not what we may be.' And that's true for all of us," says Bob. "We don't have any limits on our expectations for her any more.'' Mia Goleniowska has written a book for siblings called 'I Love You Natty' (available from Amazon). Hayley's blog is downssideup.com

The Telegraph, London