Today, I got news that a close friend is in the early days of what might be a difficult pregnancy. Richard Dawkins’ opening remarks of his book “Unweaving the Rainbow: Science, Delusion and the Appetite for Wonder” came to mind. He marvels at how statistic-numbingly lucky each one of us is to have survived the odds of a sperm and a ovum fusing and giving rise to a living cell. How we are a nanoscopically small number of the total combinations that are possible for the human genome. But as a developmental biologist, for me, this is just the starting point of the great obstacle course. The hurdles that the embryo will clear in the mother’s womb to make it to light and sunshine, warmth and fragrance, and the colours and music of this, our second home. We see numerous reminders of each step that falters, in the birth defects that abound our world (according to statistics, 3-6% of infants born). A less than perfect infant brings anguish for the mother and potential disa...