We live in troubled times, where scientific research - at least in popular forums like newspapers - is only ever critiqued by ad hominem attacks on the person who did it. Evidence showing that MMR is safe was rubbished, because some researchers once accepted a drug company ballpoint; and similarly, when the MMR scare died in the popular imagination, it wasn't because of the evidence, but because Andrew Wakefield was shown to have personally profited from legal cases and applied for potentially lucrative patents for the alternatives to MMR. It would have been less complicated if everyone had just looked at the data.

But how bad would someone have to be for you to completely disregard the findings from their research, simply on the grounds of who they were? An adulterer? A recipient of private consulting fees? How about a cold-blooded racist, homophobic mass murderer?

This Sunday a smoking ban comes into force. In 1950 Richard Doll and Austin Bradford Hill published a preliminary "case-control study" - where you gather cases of lung cancer, and find similar people who don't have the disease, and compare the lifestyle risk factors between the groups - which showed a strong relationship with smoking. The British Doctors Study in 1954, looking at 40,000 people, confirmed the finding.

You wouldn't know it, but the Nazis beat them to it. The Germans had identified a rise in lung cancer as early as the 1920s, but they had suggested - quite reasonably - that it might be related to exposure to poison gas in the great war. In the UK, Doll and Bradford Hill were wondering if it might be related to tarmac, or petrol. Then, during the 1930s, identifying toxic threats in the environment became an important feature of the Nazi project to build a master race through "racial hygiene".

In 1943 two researchers, Schairer and Schöniger, published their own case-control study in the journal Zeitschuft für Krebsforschung, demonstrating a relationship between smoking and lung cancer almost a decade before any researchers elsewhere. It wasn't mentioned in the classic Doll and Bradford Hill paper of 1950, and if you check in the Science Citation Index, the paper was referred to only four times in the 1960s, once in the 1970s, and then not again until 1988. In fact, it was forgotten.

It's not hard to understand why: Nazi scientific and medical research was so bound up in the horrors of cold-blooded mass murder, and the strange puritanical ideologies of nazism, that it was almost universally disregarded, and with good reason. Doctors had been active participants in the Nazi project, and joined Hitler's National Socialist party in greater numbers than any other profession (45% were party members, compared with 20% of teachers).

Figures on the smoking project included racial theorists, but also researchers interested in the heritability of frailties created by tobacco, and the question of whether men could be rendered degenerate by their environment. Research on smoking was directed by Karl Astel, who helped to organise the "euthanasia" operation that murdered 200,000 mentally and physically disabled people, and assisted in the "final solution of the Jewish question" as head of the office of racial affairs.

Earlier this year this paper ran a news story in which criticism was made of Sir Richard Doll, suggesting that his impartiality was somehow affected simply because he had occasionally accepted finance from industry. But medical statisticians like Doll save lives on a scale in the millions.

What would it take for me to doubt Doll's data? If you showed me he was a cold-blooded racist mass murderer, I'd still read his papers carefully.

Please send your bad science to bad.science@theguardian.com.