Too little sleep affects male fertility

SLEEP deprivation damages men’s fertility, a new study suggests.

Levels of testosterone dropped by 1.5 per cent for every hour of sleep lost, researchers from the University of Miami found.

The average man in the study slept for 6.9 hours a night, but any less than this caused testosterone levels to start to fall, according to one of the first studies to link sleep with a drop in the hormone.

♦ Erectile dysfunction could be blamed on fathers, after scientists discovered a genetic link. Variations of a gene called SIM 1 was found in 26 per cent of men who suffered from erectile dysfunction, in a study of more than 250,000 people.