"Things I once thought unbelievable in my life..."

Listening to 6 Music as I start to write about a new test that may be able to accurately predict the onset of a woman's menopause and suddenly PJ Harvey's voice pulls my attention to her lyrics: "Things I once thought unbelievable in my life have all taken place...."

But rather than it make me think about the benefits of this new medical innovation, it turned my thoughts to the limitations of it.

Iranian doctors believe that by measuring levels of a hormone called Anti-Mullerian Hormone (AMH), they can accurately predict within 4 months when a woman may go through menopause, offering women better control over their fertility and giving them a more informed choice of when to start a family.

As menopause alone is not the only factor limiting a woman's fertility (according to one expert, fertility begins to drop from the age of 28, and by 30 one in three embryos will be genetically flawed), I really can't see the benefits of this test. If anything it just provides a false sense of security, when in fact life is anything but predictable.

When I was growing up in the eighties, there was a lot of talk about finding a genetic cure for CF. Well its now 2010 and there still isn't one. In fact, there isn't a single cure for any genetic illness to date. Thankfully even in my early teens I never pinned my hopes on a cure. I just knew I had to live the life I had available to me in the best way I knew how. This was nevertheless more problematic than it might seem. The life expectancy of CF has never been something to be happy about, but even knowing it is limited doesn't actually mean much as some CF patients die very young while some make it to a pretty decent age and even have children. The variability is massive.

So you end up trying to straddle two life philosophies simultaneously - living life for the moment as well as planning for an unpredictable future. So do you jack in the job you hate to go travelling since life is too short to waste on being miserable? Or stick it out in the hope that it leads to a better job in a year's time which would provide more long-lasting happiness than a two-month jaunt around Thailand? I don't know the answers, just that you always somehow find a solution to the new challenges life throws at you.

So back to the issue of fertility. It's a precious thing, and it becomes even more precious as you get older. Innumerous medical tests can't actually come close to predicting the unexpected nature of life. Meeting the right person, getting pregnant from a one-night stand, losing a stable income, getting a great new job, losing a parent and a future loving grandparent, getting cancer, IVF that works, IVF that fails. All this stuff of life is just as important as how many eggs you have left. Perhaps having a baby should be more about what you'd need to sacrifice at any given moment to have a child and whether that sacrifice is worth it for you in comparison to a potential future without children. (And, as an aside, surely society would be better off investing in flexible working patterns and innovative child care solutions to reduce the sacrifice a woman must make when it comes to employment prospects, rather than focus on ever-new ways to extend a woman's fertility beyond its natural peak?).

Even as someone so dependent on medicine to stay alive, for me science alone has never been able to deal with the real difficulties of living. And it brings me back to PJ Harvey's lyric: information and imagination alone won't let you create a future. The real life-affirming question is: "What do you choose?"