IVF is a perfectly valid solution for the childless, but it is not the only solution, says Max Pemberton

Man + woman = baby. A simple enough sum. Of course, as with many equations, things are far more complex than they seem. Over the past 40 years, the stereotypical idea of family dynamics has drastically changed. I actually suspect that families were never that simple, but old social mores made it unacceptable to discuss the fact openly.

Being a doctor gives you the wonderful ability to ask the most probing questions about people's personal lives without getting slapped. Having talked to patients from all walks of life, it seems to me that no one has a "normal" family. But the growing proliferation of IVF treatments means that our idea of what constitutes a family can be further altered.

There were lots of issues thrown up by the court case between Natallie Evans and her ex-partner Howard Johnston last week. In 2001, the couple underwent IVF treatment after Miss Evans was diagnosed with ovarian cancer. Six embryos were created and frozen. A year later, however, the couple separated. Last week, the European Court of Human Rights denied Miss Evans's request to have the embryos implanted against her ex-partner's wishes. There was the heart-wrenching spectacle of a tearful Miss Evans pleading to be allowed to become a mother.

But, of course, she can become a mother. Adoption has become an almost dirty word in this brave new world of the genetically savvy. What lies at the very core of this case is Miss Evans's desire to become a mother, but to become a mother to children that are genetically hers. She is not alone in this quest. There is an increasing belief that we are defined by our biology. We no longer have the traditional image of the nuclear family to give us our sense of belonging, so we look to ideas of genetic heritage to provide it for us.

Parenthood has ceased to be about bringing up children - taking them to Scouts, reading them a bedtime story or shouting at them for not eating breakfast, or, indeed, any of the countless things that contribute to making children who they grow up to be. Instead, it is increasingly viewed in terms of preserving your genetic information. It is functional; Darwinian.

But this reductionist view of parenthood completely misses the whole point of parents. It ignores the enormous impact that environment has on child development, and it strips away the power of human agency. As genetics has risen in prominence, so has the belief that it holds the answers to all our questions. Society's love affair with this branch of science is understandable. It suggests that somewhere, in the twists and turns of the double helix, the secrets of happiness and enlightenment can be found. We ceaselessly seek to attribute all aspects of being human to genes and ignore the science's shortcomings.

Being a parent means that you can have influence over another human being during the most formative years. The effects of parenting last a lifetime. Infertility can be a devastating condition and adoption is not an easy solution. But it is also not easy being a parentless child. The drive to have children that are genetically ours is an entirely intellectual one.

IVF is a perfectly valid solution for the childless, but it is not the only solution. It is a privilege that only a small proportion of the world's population has access to, and it has only been a possibility for a tiny fraction of human history. Increasingly, we emphasise nature over nurture and, while IVF may have offered hope to many, it comes at a cost. By making parenthood a ''right'', have we de-emphasised the responsibility that comes with it and forgotten the role that parents play in child development? Have we not mistaken the overwhelming desire to bring up a child and share in its life with the intellectual concept of genetic heritage?

The greatest sceptics I know concerning the limitations of genes as a means of understanding humanity are, in fact, geneticists. They know that far more goes into making a human than just what we can understand from what is written down in the genetic blueprint. If only the rest of us could realise that we are, thankfully, far greater than the sum of our parts.