Making headlines (or at least the odd downpage snippet) last week: the keynote speech at the European Society of Human Reproduction and Embryology's annual conference in Prague. According to Dr Laurence Shaw, deputy medical director of the Bridge Centre, a fertility clinic in London, UK, the recent spate of IVF births to women in their sixties is nothing more nor less than the latest step in human evolution.
The general thrust of his argument goes thus: we (hom sap - or of course, in this specific case, fem sap) have been around for over 150,000 years, but it's only in the past hundred-odd that we have had an average longevity of over fifty or so. So the menopause - and the general decline in female fertility once we enter our thirties - is an evolutionary adjustment to the expectation that we simply wouldn't make it any further. We also, he adds, had our babies "when they were in their late teens and early twenties when their fertility was at its peak. In the subsequent 20 to 30 years, they raised their children, and their declining fertility meant that they were less likely to have further children of their own and could help their daughters to tend their own babies."
"The accelerated decline in fertility," he continues, "rather than the menopause itself, is the evolutionary adaptation that has occurred in the human line over the past 2.8 million years, and, until the last 150 years, the postmenopausal state and the prior decline in fertility was positively useful. Living through the menopause and beyond is not a part of our natural life."
He goes on to point out that nowadays a woman of sixty has a life expectancy of eighty to ninety, which would be roughly equivalent to the average years a woman of twenty would be likely to have had to care for her offspring a century ago. Ergo: despair not, ladies! Motherhood can be a retirement hobby, like knitting!
Um, yes. Nothing like a spot of hyperbole to get the discussion rolling, but really: this speech isn't a clarion call for a Brave New World. It's an object lesson in why scientists really, really shouldn't be allowed to argue their own cases. It reads like a philosophy paper in distorted reasoning. There are so, so many flaws in Dr Shaw's thesis that it's hard to know where to begin.
I don't want to rain on anyone's parade. Womankind has benefited from all sorts of medical advances, and hooray for that; and if someone has the wherewithal, energy and will to go through IVF, then good luck to them and the children that might result from their choices. In some ways, given the current general trend of women reproducing in smaller numbers or not at all the higher their qualifications and career success (and therefore, likely intelligence), it would be no bad thing if we supported women in reproducing more than we do, simply for the sake of the gene pool.
But natural it ain't, and more importantly, evolution it ain't; any more than the fact that we can hurtle through the sky at a thousand-miles-an-hour means that we have developed the ability to fly. Dr Shaw's argument is based on a number of false assumptions, most of them about the nature of evolution. Societies have evolved, certainly, but the human body has remained pretty much static since we stopped using our knuckles to walk.
Number one: there is little evidence that tight-knitted lifetime family units were particularly the norm in the scattered nomadic Paleolithic age 30,000 years ago, let alone 100,000 years before that. Given the sparse density of the global population and the unlikelihood that incest was the norm, the chances that your average woman would have even met her grandchildren are fairly slim. The whole extended family thing only really began when we started settling in fixed communities. If menopause were any sort of evolutionary adaptation, it would be much more likely to be related to the physical strain that pregnancy and suckling put on an ageing body than some reflection of advanced-society granny-looks-after-the-kids mores. The fact that the much less physically draining male fertility continues throughout life would suggest that this is so.
Secondly: the longevity argument. Look: we haven't changed that much. Archaeology doesn't suggest that we've even got much brighter; it's simply that our body of knowledge has increased and our capacity to build ideas on ideas has got exponentially greater as a result. And as a consequence, disease control has improved. Actually, if you were a Neolithic woman and you managed to dodge cholera, smallpox, diseases of infancy, blood poisoning, death in childbirth, dysentery, malaria, cancer, accidents and all the other lurking dangers the world has to offer, you had a good chance of surviving to seventy at least. The biblical threescore and ten isn't an example of poetic license. So, no: our increased longevity is not a result of an evolution in ourselves, but an aspect of the fact that we evolved higher brain function the best part of couple of hundred thousand years ago. Evolution would be our bodies learning to shrug off TB like the common cold, not clever people working out how to cure it.
Thirdly - and this is probably the most disingenuous off all the good doctor's arguments - since when were longevity and healthful vigor the same thing? It's all very well saying a woman has an extra thirty years to see her offspring through to maturity now we regularly make it to ninety, but come on: with all the will in the world one can't claim that there aren't differences between a woman of twenty and a woman of sixty-three, the age of oldest IVF mother reported so far. And the difference is that, however vital and energetic that sixty-three-year-old woman is, the likelihood of her becoming, in the ensuing twenty years, crippled with arthritis, bonkers with Alzheimer's or debilitated by lengthy treatments for, say, cancer, are fantastically much greater than they are for a woman of twenty. The dying process in the modern world isn't a question of skipping through the daisies until bosh, something carries you off in a matter of days or weeks; by and large it's a process of increasing decrepitude and also - sorry, but it's important - increasing financial impoverishment.
Would Darwin say that raising a child under such circumstances was an adaptation to ensure the best survival of the species? Probably not. The menopause hasn't moved up significantly over the last century because our ability to care for our offspring hasn't actually increased that much. A large number of grandparents have done magnificent jobs of raising orphaned grandchildren, but seriously: does it really make sense to start reproducing just at the point where you're about to enter the Funeral Zone?
So, look, all you creationists out there; don't go chucking yourself off the HRT just yet. If evolution is a physical adaptation in species to prevailing conditions which will ensure the best survival of offspring, then artificially induced pregnancy in those who are unable to breed naturally is certainly not evolution. Nor is it messing with the will of God, any more than using antibiotics to cure pneumonia is. There is the potential for wonderful outcomes from the current advances in infertility treatment; but please, scientific community, take note: disingenuous abuses of vocabulary will not further the human race's cause by one tiny chromosome.