REPORTS of the imminent death of the male Y chromosome have, to quote Mark Twain, been greatly exaggerated, researchers have said.

Some experts believe the dwindling Y chromosome, which determines male characteristics, is on the way out and even that men could be extinct in five million years.

But now it might be time for chaps to break open the beer and breath a sigh of relief. A new comparison of Y chromosomes in 16 African and European men indicates that male genes are here to stay.

"The Y chromosome has lost 90% of the genes it once shared with the (female) X chromosome, and some scientists have speculated that the Y chromosome will disappear in less than five million years," said US evolutionary biologist Dr Melissa Wilson Sayres, from the University of California at Berkeley.

"Our study demonstrates that the genes that have been maintained, and those that migrated from the X to the Y, are important, and the human Y is going to stick around for a long while."

Today women have a matched pair of X chromosomes while men have an XY pair. Because the X and Y cannot swap genes it is more difficult for mistakes in the Y chromosome to be corrected.