My eyes boggled earlier this week as I leafed through The Guardian newspaper and came across the story of an Indian woman who had just had her IVF baby boy safely delivered. The woman, Daljinder Kaur, was reported to be 72 years old – her husband, Mohinder Singh Gill, 79. It was their first successful pregnancy in 46 years of marriage. The eggs had been donated of course – nobody’s ovaries perform at that great age – but this septuagenarian uterus had managed to implant an embryo and its owner carry the subsequent fetus successfully to term. And it wasn’t the first geriatric pregnancy achieved by the head of the Test Tube Baby Center in Hisar, Anurag Bishnoi.
Stories like this invite us to believe that there is almost limitless potential for human reproduction, especially when it is assisted by reproductive technologies like IVF. And it is probably not for us to judge on the advisability of two seventy year-olds embarking on child rearing for the first time even if we grimly suspect that endless hours of night nursing and nappy-changing, at that age, will inevitably take their toll. Indeed, a brief overview of our apparently crowded planet – 7.4 billion people and counting – also gives us an inflated picture of human fecundity. But the truth is that we are one of the least fecund species on the planet – as the 46 fruitless years spent by our Indian couple show – and a number of reproductive biologists, informed by evolution, are beginning to unravel the inside story of human fertility to explain why. It involves a staggering amount of genetic abnormality in human early embryos, the huge costs, particularly in humans, of maternal investment in offspring, and a challenge to the tenets of assisted reproduction technology.
It only involved 23 good-quality human embryos, and was rather discreetly published as a technical report in Nature Medicine, say reproductive scientists Jan Brosens and Birgit Gellersen, but it may have changed our understanding of human reproduction for ever.