The equation for a perfect sperm? It’s
IT IS a mass of mathematical symbols that you might expect Professor Stephen Hawking to use when probing the secrets of the Universe.
But the baffling equation above could actually help define the ‘perfect sperm’ – and hold the key to fertility for couples hoping to conceive.
Devised by British scientists, the algebra describes how efficient a sperm is when moving towards the egg, taking into account factors such as the length of its tail and the rate at which it oscillates. It is just one of a series of equations that scientists hope will help couples undergoing fertility treatment by enabling them to use only the most efficient specimens.
The Birmingham University team even think the maths will help them create a mobile phone app that rates a man’s fertility in seconds, by analysing magnified images of sperm samples. Project leader Dr Dave Smith said: ‘This has the potential to transform fertility treatment.’
One in six couples has trouble conceiving, and faulty sperm are thought to be a factor in half of cases. But gauging the quality of a man’s sperm remains an inexact science, leading to uncertainty about treatment.
Professor Allan Pacey, an expert in male fertility at Sheffield University, said: ‘Identifying sperm that are up to the job is actually very hard to do. The principles behind the current test date from 1952.’ Improving semen analysis, he said, was seen as ‘the holy grail’ for doctors like him.
Currently specialists use a microscope to count the number of moving sperm in a semen sample. They also look at the shape of sperm – but the judgments they make are subjective.
For men with very poorquality sperm, identifying the best individual candidate to inject into a woman’s egg is even more challenging – compromising success rates.
The Birmingham team believe they can drastically improve accuracy by automatically measuring vast numbers of sperm using high-powered cameras, then analysing which are best using computers.
‘Then we remove the human error that comes from looking and counting them,’ said Dr Smith, To do this they are examining two factors in particular: how well sperm move, and the shape of their heads.
His colleague, Dr Jackson Kirkman-Brown, said: ‘If a sperm can’t get to the egg, it has got no chance of fertilising it. So swimming ability is critical.’
However, sperm don’t swim in straight lines ‘like Michael Phelps’, Dr Smith said. ‘They basically have to swim through mucus, and to do that they snake through it in an S-shape’ – and the equation above describes how efficiently they do that.
He said the other important factor was how ‘tidily’ the sperm’s DNA payload was packed into its head. Sperm are tiny – their bodies about five thousands of a millimetre long – but Japanese researchers have already taken detailed pictures of them on a phone camera adapted with a magnifying lens.
Dr Smith, whose research is funded by the Engineering and Physical Sciences Research Council, said pattern-recognition software could then process the data on the phones.