Smoking has a number of effects on health

The study, by the British Medical Association, says smoking has caused impotence in 120,000 men aged 30-50.

It is responsible for up to 5,000 miscarriages a year, reduces the chances of successful IVF and is implicated in cases of cervical cancer.

The BMA is calling for tough anti-smoking measures, including help for pregnant women to avoid passive smoke.

BMA recommendations Women exposed to passive smoking at work should be entitled to leave of absence on full pay throughout their pregnancy Tobacco warnings should include risks to reproductive health Smoking should not be glamorised in the media Government targets to reduce smoking should be more ambitious Enclosed public places should be smoke-free

The report concludes that the damage inflicted by smoking is evident throughout reproductive life - from puberty to middle age.

Not only can smoking prevent people starting a family, the report says, it can also damage their children.

It says smoking reduces the chances of a woman conceiving by up to 40% per cycle.

And women who smoke during pregnancy are three times more likely to have a low birth-weight baby. Low birth weight is closely linked to illness and death in infancy.

There is also evidence that smoking may increase the risk of certain foetal malformations, such as cleft lip and palate.

Women who smoke have also been found to produce smaller volumes of lower quality breastmilk.

Passive smoking is linked to cot death, premature birth, respiratory infection in children and the development of childhood asthma.

It is estimated that each year more than 17,000 children under five years old are admitted to UK hospitals because of respiratory illness caused by exposure to other people's cigarette smoke.

Dr Vivienne Nathanson, the BMA's Head of Science and Ethics, said: "The sheer scale of damage that smoking causes to reproductive and child health is shocking.

"Women are generally aware that they should not smoke while pregnant but the message needs to be far stronger.

"Men and women who think they might want children one day should bin cigarettes.

"And we're not just talking about having children. Men who want to continue to enjoy sex should forget about lighting up given the strong evidence that smoking is a major cause of male sexual impotence."

Devastating impact

Deborah Arnott, director of anti-smoking charity ASH, said: "This report clearly shows the devastating impact of smoking on generations to come.

"Stopping smoking should be the number one priority for anyone who wants to have children.

"This is important not just to increase the chances of conception but also to give your child the best start in life.

"By stopping smoking, parents will not only improve their own health but will lessen the chances of their children developing illnesses such as asthma and pneumonia."