‘The fifteen-minute race has been an uphill battle – only a few thousand sperm out of hundreds of millions have made it to the final stretch. Swimming furiously up the fallopian tubes at a few millimetres per second, helped along by contractions of the tubes’ walls, millions die along the way in one of the world’s most competitive marathons. The remaining sperm plunge their little heads into the outer layer of the egg wall, releasing enzymes that weaken the tough ramparts. Finally a single sperm manages to penetrate the wall and, within seconds, reaches the inner membrane layer that surrounds the egg’s cytosol. There it fuses its complete contents with the egg, so that sperm and egg become a single cell. Within a few more seconds, other enzymes are released from the cytosol to render the egg wall completely resistant to any further interlopers, and the wall remains intact for another five days yet, just to make sure. A few other sperm that make it to the finishing line knock their heads on the wall in vain.
Each of our lives began this way…Had another sperm swum just that tiny bit harder, then you could so easily have been male rather than female, or vice versa, but then of course ‘you’ would have been someone else altogether.’
That was the beginning of chapter 3 of Denis Alexander’s new book, The Language of Genetics: An Introduction. It makes me laugh – I imagine that was the desired effect – but it’s a great description of the beginning of life. I’m not sure about the wisdom of anthropomorphising sperm, but it does get across the urgency of the ‘race’, and highlights how unique each of us is. The scientific detail is interesting, and helps to illustrate something I’ve mentioned before that I think is often missed in natural theology – generosity.
I was at a meeting of Christians working in science a couple of weeks ago, and someone prayed a prayer that included thanking God for his efficiency in nature. Efficiency?! Millions of sperm for one individual? The earth’s crust packed full of useful ores, precious stones and energy-rich substances? Free energy from the sun, wind and waves? Plants that produce food from sunshine, air and water? I think these are examples of God’s great generosity in producing an abundance of resources*. Of course efficiency is something we need to think about when we use natural resources, but those resources are provided on a spectacular scale. I need to make sure that I don’t create my own God – in the image of a divine time and motion technician…
*I know that the production of thousands of gametes in reproduction is an adaptation to ensure successful reproduction, but I still think it flies in the face of the images that Christians sometimes use of God running everything very efficiently – as if overabundance might be a waste. That’s not what we see in nature.