So when her killer strangled her on Boxing Day two years ago, he did not just take the life of another woman living alone. He was snuffing out a dream shared by many, realised by few. Joan's funeral in west London was attended by some of Britain's leading doctors; she was buried wearing her stethoscope. Her two sisters, Margrette and Celia, had fixed her hair after the post mortem and chosen a favourite black gown from her wardrobe. Joan had been due to fly to Los Angeles on the day she was killed to spend the end of Christmas with her sisters. When she was late, the police, finding the back door open, discovered her dead. Celia and Margrette flew to Britain to identify the body next day.
So it is hardly surprising that Joan Francisco's equally extraordinary family is unwilling to let the matter rest, refuses to accept that lack of evidence rules out bringing her alleged attacker to trial. The Francisco family may have lost a daughter, but will not let perish their belief that determination eventually wins out.
They recently announced a highly unusual civil action against Tony Diedrick, a former boyfriend whom they believe killed Joan. The law does not allow a civil suit for murder, so they have instead made a claim for assault and battery. Mr Diedrick, 37, from Maida Vale, north-west London, would, in a criminal trial, be allowed to remain silent. In a civil court he would have little option but to mount a defence and give evidence. And whereas conviction in a criminal trial requires guilt to be proven beyond reasonable doubt, in a civil court it is enough that the balance of probability points to liability. The family is seeking damages of up to pounds 50,000, including more than pounds 17,000 for the funeral bill.
If there appear to be parallels with the case brought in California against OJ Simpson by the families of Nicole Simpson and Ronald Goldman that is hardly surprising, given that Margrette and Celia, though educated in London, are now lawyers in Los Angeles, specialising in civil litigation. Margrette also works in London for a City firm.
"I remember calling Celia after the verdict in OJ's murder trial," says Margrette, the eldest sister, a large, effusive woman who has a clear sense of mission. "Both of us wondered how we would have coped, if what happened to Nicole Simpson's family happened to us. We felt a great affinity to the family when OJ was found not guilty."
This helps explain why they are, in effect, doing OJ in reverse. "We would hope that the investigation for the civil case will turn up fresh evidence which the Crown Prosecution Service would then use to bring forward a criminal prosecution."
The family could have started a private criminal prosecution, but were wary of what happened in the case of Stephen Lawrence, the 18-year-old black A-level student who was murdered by a gang of racists. The Lawrences' case against the three accused collapsed after vital identification evidence was ruled inadmissible. "We can't afford to go into court and not win," says Margrette. "An individual cannot stand trial twice for the same criminal offence." The Francisco family is represented by JR Jones, the firm of solicitors who acted for the family of Stephen Lawrence.
Talking to Margrette, you sense the energy that Joan is said to have shared, a vigour cultivated by her father, Alfred, from Belize, who until his retirement taught maths, physics and technical drawing in a secondary school, and her mother, Venus, from St Lucia, who is still a nurse.
Margrette, 36, an enthusiastic smoker with a passion for frequent, strong cappuccinos and plenty of sugar, is certainly driven. She recalls the family moving to Saudi Arabia for a couple of years when the three sisters were young children. "Father taught us at home, as though he was teaching secondary school students. So I learned geometry and algebra at the age of six. He taught Joan to use a slide rule when she was five. He encouraged us to have seeking minds and always to be curious. For example, the house we lived in had a flat roof, so he would take us out on to it at night and show us the constellations.
"In London, we went to a majority white school, where I ended up head girl. The reason we all fitted in was because we didn't regard race as an issue. What we projected was what we expected and what we received."
All three sisters did well, but Joan, the baby, was the star. "She was the most focused of all of us. When she had to study, she wanted everybody else out of way. She would listen to study tapes in her sleep in the hope that she would learn subliminally. I remember she gave up chocolates for Lent and then later decided it wasn't wise for a child to eat them. So, at the age of nine, she gave up for good. At one stage, she decided that white flour wasn't good for her, so she baked her own bread every morning.
"But it wasn't just work, work, work. She loved to dance. She played the piano. At school, she ran track, did the high jump and played net ball. She swam a lot, she modelled - Joan was very in tune with her body."
Her potential was not always appreciated at school, which is why the family has created a foundation in her name devoted to supporting would- be doctors from minority backgrounds. "When Joan wanted to apply to medical school," says Margrette, "she was told she would not get in, even though she had all As at O-level. I told her to disregard what she was told. She was accepted by all five schools she applied to and chose the Royal Free in Hampstead.
"We created the foundation because after Joan's experience we thought about kids who may get caught in a system which is not encouraging. A lot of parents rely on teachers to give children their best chance. But sometimes teachers are biased or don't know how to get the best out of them. Providing a mentor - someone who already does the job - can help a child to make the series of small steps necessary to travel from aspiration to goal." Last year, the foundation provided three scholarships of pounds 1,000 to medical students.
"I believe," says Margrette, "that you must create something of value out of whatever happens. Getting through this court case hopefully will enable us to close a chapter that has been very painful and difficult." The family has chosen a gravestone which will cost pounds 10,000. They intend that whoever killed Joan should pay for it