Sperm know the way?

Human sperm have been shown to have a form of 'memory' for directions. Peter Brugger, a Swiss scientist, tested sperm in a maze, recording the way 714 individual sperm turned at a T-junction. Testing the behavioural differences of sperm might be one way to check whether sperm being used in fertility treatments are healthy.

Brugger found that in sperm faced with a choice between two directions, half would go one way, and half the other. But if the sperm cells had previously been forced to turn in one direction, a greater proportion of them would turn in the opposite direction when they next could. He believes that if the 'maze' he used were smaller, a higher percentage of the sperm would take alternate directions when turning, indicating that over shorter distances, a sperm's 'memory' might be better.

There are a number of different suggestions as to why sperm should behave in this way and more experiments will be undertaken to find out, including one putting sperm through a maze one at a time.