When Edward Batha's newborn daughter was diagnosed with Down's syndrome, he thought it would spell a lifetime of suffering. But one year on, her resolute character and sunny nature has led him to rethink what it means to be a member of society

After a traumatic birth last August, we were informed sympathetically that our daughter had Down's syndrome. We struggled to come to terms with how something so full of promise could suddenly morph into such a nightmare. A lifetime of special needs and second-bests gaped dispiritingly before us and my fatherly dream of walking proudly down the street, holding hands with my perfect daughter, crumbled to dust.

Luckily, one of humanity's greatest assets is its adaptability. Within weeks, my wife, Tash, and I had started to accept that the map ahead for Mia would be different to the default one we'd expected. In many ways, it was lucky that she was our first child; it meant that this was not an entrenched map and we could grow together, unhindered by comparison or precedent.

Down's syndrome is medically known as trisomy 21. Most people have 23 pairs of chromosomes in every body cell. Mia has an extra copy of chromosome 21, causing her to have 47 chromosomes per cell instead of 46. During the genetic creation stage, it is not uncommon for extra copies of a chromosome to be present in a cell, but the implications for the foetus are usually so extreme that it self-terminates.

Trisomy 21 babies have one of the few chromosome imbalances that means nature deems them fit for survival. Unfortunately, one side effect was announced a few days after the birth, when we were told that Mia had two holes in her heart. In addition, the audiologist informed us that she was not responding to her hearing test. Anything else while we're at it? The order of the world seemed unbalanced; how could someone have so many tragic things happen while so many other babies move obliviously towards a rosy future?

Mia was a tiny baby and showed no discernible enthusiasm to rectify the situation. Her milk intake was paltry, despite Tash's best efforts to feed her up to 12 times a day. From the start, Mia had trouble keeping milk down. Around 1am every night, she would guzzle and slaver at the bottle for half an hour, followed by 45 minutes of trying to get her to settle. Inevitably, this would culminate in the decoration of her father with all the recently administered milk, now in a hot, rancid form. We tried to work out if this was reflux or colic; or perhaps the teat. The milk? The timing? Eventually, anti-reflux concoctions were added to the battery of medicines we were already administering by syringe four times a day, and, although the situation was still bad, it did head off the threat of the nasogastric feeding tube.

The weekly weigh-in with our GP, Dr Brunner, showed a growth that ghosted that of the smallest 5 per cent of children with Down's syndrome. At one point, just after we had started her heart medicine, Mia's weight plummeted, nearly taking Tash's sanity with it. We hadn't known that, as a diuretic, it would drain the body of all excess water.

But those early days were by no means all hardship. Like any baby, Mia's character emerged as the months rolled on. Her responses to the pain showed a resolute side to her, while her enthusiasm for life was evident in her cheerful, everyday interactions – nothing generated such joy as stealing the magazine I was reading and shaking the living daylights out of it. On Christmas Day, she rewarded us with her first laugh as we danced to The Beatles.

With her feeding almost under control, the roller-coaster process then turned its attention to her hearing. At one point, we were told the nerves from the middle ear to her brain were too damaged. This was a massive blow: without hearing, speech becomes but a distant hope. Thankfully, this diagnosis was retracted and she has been given a provisional all-clear. Likewise, the appearance of nystagmus, a flickering eye condition, settled after a while.

There is no real method of assessing where Mia stands relative to other children with Down's syndrome. Forty years ago, such a child was often separated from society at an early age. Now, the emphasis is on inclusive education and independent living, with intensive work on speech and motor skills in the critical early developmental stages. To this end, we have been assigned a portage worker, Ruth, whose knowledge and cheer galvanises our efforts to cajole Mia through the milestones of midline, holding, rolling, sitting, clapping, and onwards to crawling and standing.

Under our new status as Team Mia, Tash and I forge on, our characters contributing in different ways, frequent witnesses to the admirable side of each other's nature. There are still times when you want to scream, "I can't do this anymore," but there are many more when we are delighted to see her finally sitting up unaided, or we can say, "Look, look – she's turning the pages of the book herself!" Mia is remarkably sociable and can smile for England, melting me every time. When people say, "Aren't you a lovely little girl?" her favourite trick is to leave a perfect pregnant pause, look straight at them, then deliver a colossal raspberry followed by evident toothless glee.

Despite our immersion in the world of Down's syndrome, we had met hardly anyone else with it. Then Tash discovered Downright Excellent, a playgroup populated by children up to four years old, primarily with Down's syndrome, but also their siblings. Another appealing aspect was the parents: they were of a similar age or mind-set, and hinted at holding down lives beyond the syndrome. When we are there, our world seems like the normal one and this group has become a weekly fix of speech therapy and play for Mia, and conversation with others in the same boat for us.

In June, the Royal Brompton Hospital abruptly brought forward Mia's heart operation. Two major things can go wrong with heart surgery. First, the transfer of the tubes between heart and bypass machine needs to be done quickly enough to prevent brain damage due to oxygen depletion. Second, there's the small matter of operating on a baby's heart. Holding the gas to her face and singing as the anaesthetic began to work felt like an act of gross betrayal and we left the pre-theatre in tears. Sitting in the café downstairs, Tash discovered a zest for knitting, and set about making a blanket for Mia, every stitch borne of fear, love and hope. I just mainlined coffee, felt sick and read the paper.

Mr Sethia was the man with the scalpel and he saved our daughter's life. Four hours later, we were called up to intensive care to see our beloved Mia, who had tubes running in and out of her and was sporting a livid wound down her sternum. With everyone facing similar operations, with so much at risk and so irreplaceable, the camaraderie in the wards was intense. It took Mia three days to come round, but within a week she was partying so loudly in her cot they were obliged to discharge her.

Mia has never looked back: she hasn't thrown up once since, sleeps through the night and has put on more weight in the three weeks after the operation than in the previous six months. She rapidly grew much more robust – people are now less scared of handling her and she has been able to spend time with her grandparents, even going on a family holiday where she celebrated her first birthday. She is much more interactive, too, and we babble back and forth. The first two words she learnt were Eddie and Daddy, which I think shows what a clever girl she is – or at least how crafty.

There is no hiding from the fact that Down's syndrome adds a lot more to the workload of child-rearing. The process is, however, immensely rewarding and she is primarily and overridingly a little girl; the syndrome is a tack-on – not the definer. Increasing, I find it wrong the way that such a child is portrayed in the whole ante-natal process, as if you are going to give birth to a reject or a mongrel. In years not so distant from now, people will be able to learn what chance their children have of becoming alcoholic, depressed, epileptic and so on. Will these all become grounds for premature termination or will we be obliged to face the fact that we are all born different? And will Mia's kind be given the respect they so richly deserve?

For myself, I have no doubt about the worth that Mia's character can contribute to our world. Just by being her cheerful, stoic self, Mia has changed me. Now I know of no one whose hand I would be prouder to hold as we walk laughing down the street together.

www.downrightexcellent.org; www.downsed.org

Down's syndrome – the facts

* For every 1,000 babies born, one will have Down's syndrome.

* About 600 babies with Down's syndrome are born in the UK every year.

* It is estimated that there are around 60,000 people living in the UK with Down's syndrome.

* Attitudes towards it have changed dramatically. The 1944 Education Act had declared children with Down's syndrome "uneducable", and most were put into institutions. But Education Acts in 1970 and 1981 recognised that children with learning difficulties had the right to go to mainstream schools, and advocated the closure of long-stay hospitals.

* In 1980, nearly 50,000 people with intellectual disabilities were in hospitals. The majority had been there for more than five years – and many of them for more than 20 years. Long-stay hospitals were supposed to have closed for good in 2005, although 300 people with serious learning disabilities are still in hospital today.

Mary Morgan