But a report on vasectomy published this month is, for the most part, reassuring.
The operation itself, widely available on the NHS, is simple and safe enough: carried out under local anaesthetic, it involves cutting the vas deferens, the tube that carries sperm from each testicle to the penis. “Child-hating ER hunk” George Clooney is keen on it, according to the tabloids. Bishop Philip Boyce of Rathoe, Donegal, has branded it as “against God’s law”. One man, writing to The Sun’s “Dear Deirdre” column, said it had sent his sex drive “through the roof”; another complained it had made his wife too randy. A woman at an auction in Devon, meanwhile, bought it for pounds 70 as a present for her husband. Vasectomy, or male sterilisation, introduced in Britain in the Sixties, is fast becoming a popular contraceptive option, with about 90,000 men undergoing the operation annually (although according to one London clinic, it is usually the woman who suggests it).

For each of us who has been diagnosed there are another 10 out there struggling along, not knowing what is wrong. They are fobbed off by being told there is nothing wrong with them, or they are given the wrong diagnosis or treatment”nThe UK Narcolepsy Association , 1 Brook Street, Stoke on Trent, Staffordshire, ST4 IJN (01782 416417).. But I missed out on so much before I was diagnosed.”Michael Sergeant, chairman of the UK Narcolepsy Association, says sufferers typically delay for years before seeking help, and are then dismissed by GPs who tell them to buy a bigger alarm clock or go to bed earlier “It is totally humiliating. If she laughed or got excited her knees would weaken, her jaw would drop and her eyes would roll.

But she couldn’t persuade her GP to take an interest.”It is hard to convince people of how much you are actually sleeping. I then changed doctors and was referred to a consultant neurologist. He said I was a textbook case of narcolepsy.”Now married, with two children, she is being treated with drugs which have successfully controlled her condition “I am lucky – not everyone responds so well. She would drop off in discos or on country walks if she sat down for a rest.

Stimulant drugs, based on amphetamines, help keep some sufferers awake during the day, but they tend to develop tolerance, requiring increasing doses, with a greater risk of side effects.Kathryn Appleby, 32, has suffered from the condition since she was 18 but was not diagnosed until she was 25. Anything that suddenly increases the level of alertness can trigger an attack. It is socially disabling.”In the UK an estimated 40,000 people are affected, but only 3,500 have been diagnosed. One of the worst features is a sudden loss of muscular control, called cataplexy, whenever a sufferer becomes excited. The effects include shaking of the jaw, slumping of the head and buckling of the legs.Dr Meryl Dahlitz says: “You make a joke, hit a good shot at tennis or get angry, and you collapse. Daytime sleepiness caused by narcolepsy and other sleep disorders is the commonest cause of fatal car accidents.It is an inherited condition whose cause is not understood, although there is growing evidence that it is linked to a disorder of the immune system.