How much do you want to know about your baby?

Clare Epstein and her husband opted for genetic tests before trying to conceive a longed-for second child by IVF. But a shocking discovery made them wonder how much knowledge is too much

Genetic testing, with its inherent promise to predict and control the future, is deeply seductive, and at its best is a powerful tool for bypassing heartache. (Rex)

Our crystal ball was made of spit. One morning a few weeks ago, my husband and I filled two plastic vials with gobs of our DNA, packaged them up with our credit-card details, and posted them off to a hi-tech fortune teller, who would read them like tea leaves to reveal our genetic future. We were doing this at the urging of our doctor, a fertility specialist at the American clinic where we are about to undergo in vitro fertilisation (IVF) to produce a much-longed-for second child. (Our first was made the old-fashioned way, scrambling our genes one night after a Christmas party.)

We live in the United States, where genetic testing is commonplace, not just before IVF, but as part of routine medicals, and through direct-to-consumer private companies. As well as adding a new dimension to dinner parties – where hypochondriacs can now regale you not just with their past medical highlights, but their future ones too – it also creates an entirely different culture of medical risk. Before even considering starting an IVF cycle, our doctor strongly urged us to undergo something called the "Jewish panel of tests". It was a name that conjured up my fears about the first Friday night I spent at my future in-laws' house, as they subtly tried to scope out whether I, half Jewish, could possibly be a suitable candidate to marry their beloved elder son. As it turned out, my spit was the perfect means of convincing my husband's family that I was kosher. It revealed that I am a carrier of a rare Jewish genetic disease. Unfortunately, my husband's saliva showed up the exact same gene mutation, a situation that means that any of our offspring, including our 20-month-old son, has a one-in-four chance of being affected by the disorder.

The results came through by email, a form letter with scant information about what this might mean in practice. Our doctor at the IVF clinic, while sympathetic, admitted knowing little about the disease, and referred us back to the testing company. Its helpline spiralled me through one perky menu cul-de-sac after another, all of them ending bleakly in voicemail. Unable to locate a human being who might help us to decode our fate, I spent a dark weekend alone with Google, swilling through horror stories with no means of interpretation. Wikipedia informed me that symptoms can start at any time – at worst they can include rapid and complete neurological degeneration and death by early childhood. My universe stopped.

By Monday, I was desperate to talk to a medical professional who could help us to understand. I soon realised that in the devolved and highly specialised American healthcare system, in which different branches of medicine are largely disconnected, it was almost impossible to get any answers. Our son's paediatrician had never heard of the disease, and the local children's hospital seemed similarly confused by our request. The genetic-testing company eventually offered us a telephone appointment with its counsellor, but it was brief, and sketchy on the details.

As I tried to navigate the bureaucracy, the IVF clinic dangled the option of something called pre-implantation genetic diagnosis, or PGD. For a fee of around $8,000, any embryos we produced could be tested for the offending gene, and affected ones would be destroyed. Further testing could be done in pregnancy. Any rogue foetus that had managed to wriggle through PGD's clutches could, they assured us, be terminated. We jumped at it, desperate to outsmart tragedy.

But this sci-fi solution didn't help our existing son, and I was still struggling to find out what all this meant for him. Finally, I managed to track down a specialist in the condition. After a long and detailed conversation with him, suddenly the picture seemed very different. Apparently the disease has many sub-types, but in Ashkenazi Jews with our specific gene mutation, the symptoms are typically mild, do not start until early adulthood, and are virtually 100 per cent treatable with a series of injections. For us, this diagnosis didn't justify the destruction of an otherwise healthy embryo, much less the termination of a much-wanted pregnancy. When the relief started to subside, we felt as though we had been subtly pushed down an expensive and destructive path.

Genetic testing, with its inherent promise to predict and control the future, is deeply seductive, and at its best is a powerful tool for bypassing heartache. But the sophistication of the testing available is racing way ahead of the support services on offer to deal with the results, both in practical and ethical terms. There are more than a hundred genetic tests currently in use and their findings are difficult to interpret, even for doctors. As in our case, the prognosis for a given condition can vary wildly depending on specific gene mutations, ethnic background, environment, and a whole host of other factors. Given the complexities involved, it is unrealistic to expect IVF specialists or general physicians to be experts in hundreds of genetic diseases with thousands of variants. We are at a point where we know how to ask the questions, but not what to do with the answers.

As the technology starts to allow us to test not just for major life-threatening conditions but for milder, less tragic eventualities, the answers become less black and white, and we enter into the complex territory of amateur eugenics. My husband and I were clear that we would not hesitate to screen out an embryo with a condition that would lead to debilitating pain and death in childhood, but would we screen out a deaf child? A diabetic child? A colour-blind child? Where would we draw the line? The questions have the ring of sixth-form debating-society topics, but we lack the blind adolescent moral certainty of sixth-formers.

Our experience with genetic testing somehow cut to the very heart of what it means to be a parent. We are primed to protect our offspring from risk. On neurotic days, when the enormousness of the love I feel for my child hits my solar plexus, I would gladly sign up for a test that could detect and avert his every scraped knee, failed exam and broken heart. But the removal of all hardship in life isn't what makes for happiness. We will not be going ahead with the screening when we start IVF next month. Sometimes in life, we just have to roll the dice.

Clare Epstein is a pseudonym