Profile: Lord WInston: Glenda Cooper on the fertility doctor who has been accused of playing God
Robert Winston read Diane Blood's affidavit on her fight to have her dead husband's baby at 2 o'clock in the morning and wept. Less than two hours later, he says, he was urgently faxing his own opinion on the case to her lawyer. "It really moved me to tears. I thought `God in Heaven, how can they do this? This must be wrong'."

The Blood case is the latest controversial life-before-birth issue that has pushed Professor Robert Winston - Professor Lord Robert Winston, to give him his full title - into the spotlight. Other recent controversies have included giving fertility treatment to an HIV patient, and entering the debate about the selective termination of a twin pregnancy. His research - which includes pioneering work on screening embryos for disposition to cancer - has won plaudits from his peers while exposing him to vitriol from pro-lifers who see an Aladdin letting a dangerous genie out of the lamp. As one of Britain's most prominent fertility experts and head of the country's largest in vitro fertilisation clinic in Hammersmith, his is the medical soundbite we most frequently hear on issues such as frozen embryos, octuplet babies and twin abortions.

Now he has political muscle, too. Nominated by Tony Blair for a life peerage last November, Lord Winston is now introducing a Bill to amend the 1990 Human Fertilisation and Embryology Act to ensure that a case like Diane Blood's can never happen again.

Stephen Blood died suddenly from bacterial meningitis. While lying unconscious in hospital, sperm was taken from him so that his wife could have his baby. But, under the terms of the 1990 Act, because Stephen did not leave written consent, Diane Blood is forbidden from using the sperm despite evidence that her husband would have wanted her to have his child. She has also failed in her bid to get permission to take the sperm abroad.

Lord Winston felt frustrated that the "great and the good" were effectively deciding whether Mrs Blood should have a child, when in fact she was the best person to calculate this in the circumstances.

His proposed amendment to the Act receives its second reading in the Lords on Thursday. It would allow "in reasonable circumstances" the use of the gametes [sperm or eggs] of a dead person without written consent. Whether it succeeds or not will depend on whether the Government is willing to give it time before the general election.

Such a controversial Bill may be condemned to lie dormant. But it is unlikely that Robert Maurice Lipson Winston will.

HE WAS born in west London in 1940, son of a diamond craftsman, who died when he was nine, and a dynamic mother. Ruth Winston Fox is a former mayor of Southgate and still active in charity affairs. Winston, an Orthodox Jew, has described his rabbi grandfather as the "formative influence on my life".

As a young man, he was drawn to the theatre and medicine in almost equal measure, and in his late twenties briefly deserted the profession for the stage. His Who's Who entry still mentions his award-winning Pirandello production Each in His Own Way at the 1969 Edinburgh Festival. For more than 20 years he has been happily married to Lira and has three children, Tanya, Joel and Benjamin. Friends of the family say that there is a warm atmosphere in the house based on "core values".

And he is a political animal, a Labour life peer who is said to be close to Tony Blair. If the next government is Labour, the man accused many times of "playing God", whose energy has aroused admiration and annoyance in equal measures in the fertility establishment, the media and the public, could be determining the legal framework for medical ethics into the next century. Winston says he has no such influence but makes no secret of his admiration for the Labour leader: "I think Blair is an amazing leader in what he has done for the Labour Party and what he could do for the country. I see this man as a very important figure in politics."

His theatrical past is evident when you meet him. He is undoubtedly at ease with the media and knows exactly what he wants to get across. He pauses effectively, speaks passionately and articulately about his subject, and knows how to pose for the camera. Seated in his small office, surrounded by hundreds of pictures of the children he has brought into the world, he has a slightly comical air, but the Groucho Marx moustache and the cuff-links marked "left" and "right" do not conceal the rigorous intelligence.

Winston is utterly charming until a question displeases him. Then the temperature plummets as he sits in silence until you are forced to break it.

His warmth and affability was clear in the recent BBC documentary about the Hammersmith unit Making Babies. Off-camera, though, patients and colleagues are in awe of him. "I'm not sure whether some of his patients can see him as a man," said one source. "With some of them you can see their relief when they come out. He can be quite aggressive, someone whom people are worried about upsetting."

Winston acknowledges he can be "impatient". Of patients he has dealt with summarily he says that it is not his job to raise false hopes: "Some people need to have a clear-cut decision, if the patients are too old, if their sperm is not usable... by providing softness and not being abrasive sometimes you aren't allowing them to go through the process of bereavement."

"I absolutely enjoyed working with him," said Joanna Clinton Davis, who was the series producer of Making Babies. "He can have a very short temper but I felt you could undercut that, and he has a good sense of humour which you can appeal to".

His high media profile provokes both professional envy and admiration. One critic talks of "the Bob Winston roadshow ... There are lots of people who are doing good work in this field but they don't feel the need to tell everyone about it ... It's always Hammersmith, Hammersmith, Hammersmith".

But Simon Fishel, scientific director of Nurture [Nottingham University Research Treatment Unit in Reproduction] and pioneer of sperm micro-injection techniques, rejects such criticism. "He has been outspoken and rightly so about the way some fertility patients were treated which didn't win him friends. The profession doesn't like to be knocked by its own.

"It should be acknowledged that almost singlehandedly he has taken IVF into the political arena ... In the late 1980s the debate was whether or not we should be able to do embryo research. It was his eloquence and timing which secured it."

WINSTON was initially highly sceptical of IVF when Steptoe and Edwards started developing the treatment: "I was one of those people who thought IVF was a waste of time ... I was wrong," he says now. By 1980 he was convinced that IVF was something Hammersmith should be doing. Now it is the largest IVF clinic in Britain.

His team at Hammersmith went on to pioneer pre-implantation diagnosis. It was initially used to determine the sex of an embryo to help couples who might have a baby with a sex-linked disorder such as Duchenne muscular dystrophy, a wasting disorder affecting only boys. By 1992 the first babies had been born after specific testing for cystic fibrosis. This area of his work has brought Winston some of the most virulent attacks. For, if embryos can be screened for sex and "imperfections", then are we not on the verge of sanctioning "designer babies"?

Lord Winston acknowledges that he has been asked to select boys on social grounds but that he has always refused: "There are grave concerns about sex selection. But I have to say what we can do now is nothing compared with what we will be able to do in the future, when it will be possible to get sex selection off the shelf, and we will have to deal with the issue."

And some of these ethical issues are already pressing. His most recent research concerns families with known disposition towards certain cancers. A limited number of genes are known to cause bowel or breast cancer by the age of 30 and Winston's research helps screen out embryos that have "a 90 per cent chance of developing a fatal cancer by the age of 35".

"I agree there is a problem," he says. "Schubert died at 31. We could miss another Schubert by not putting that embryo back, but we might get a Beethoven instead. What is the alternative? Are the couple to have an abortion - and I have more difficulty with abortions [than embryo selection] - or play a kind of Russian roulette?"

It seems alarmingly near to what his critics have called "playing God", and it is a criticism to which he is sensitive. He insists that he sees himself as "embarrassingly imperfect ... I don't believe I'm playing God. I think it's quite the reverse. I'm trying to avoid making decisions for other people."

And this is a consistent theme in the cases that Winston champions. Who should decide that an HIV-positive woman be excluded from medical technology? Who should decide whether Diane Blood has her husband's baby?

"I'm not doing this just to get publicity. I do believe in doing what you can to right something that you think is wrong."