Human sperm can tell when they've taken a wrong turn - and try to get back on track, according to a researcher.

However, other experts suggest it is highly unlikely that sperm have any sort of memory or intelligence.

An average man can produce millions of sperm cells a day.

These are highly specialised, designed to "swim" forwards with a thrashing tail or flagellum.

Apart from this, however, they are little more than a bag designed to carry genetic material to fertilise the egg.

However, researchers at University Hospital Zurich have found that sperm appear to have hidden abilities.

They allowed hundreds of sperm to swim towards a t-junction offering a left or right choice.

As expected, half of them headed right, and half headed left.

Back on track

However, when an extra right hand turn was introduced before the sperm reached the junction, 58% of them turned left.

It is possible that sperm can react to chemicals produced by the egg

Dr Matthew Gage, University of East Anglia

Dr Peter Brugger, the neurobiologist who conducted the tests suggested that the sperm have an innate ability to "correct" the original right turn by choosing to turn left later on.

This keeps them heading in as straight a course as possible.

He believes that the sperm might even be communicating in some way with each other.

Another explanation is that the right turn may cause a physical change in the sperm's tail, which then leads to the "correction" later on.

Dr Matthew Gage, from the University of East Anglia, who carries out research into sperm function in animals, said it was highly unlikely that sperm were capable of any form of cognitive thought.

However, he said, sperm behaviour could change, perhaps as a result of a simple biological switch prompted by changes in chemicals.

He said: "It is possible that sperm can react to chemicals produced by the egg.

"These are the most specialised cells produced by the body, and there's still a great deal we have to discover about them."