Of all the MPs who could have been appointed to the health select committee on Thursday, Conservatives Nadine Dorries and David Tredinnick are perhaps the most controversial choices. One attracted ridicule for claiming that an unborn foetus could punch its way out of the womb, while the other is a supporter of astrology who once asserted that blood doesn't clot under a full moon. The inclusion of either on any select committee is worrying, but for both to have been elected to the health committee is an extremely disturbing development.

Mid-Bedfordshire MP Nadine Dorries has been involved in select committees before. As a member of the innovation, universities, science and skills committee, she achieved an attendance rate of just 2%. Having dipped her toe in the water, she then took up a place on the science and technology select committee, but clearly at this point she had overstretched herself, because she failed to attend a single meeting. Critics will be hoping that she maintains the same record at health – certainly I'd happily bet dinner on Nadine's attendance failing to reach double figures in her new role.

Dorries' primary interest in the health arena is abortion, a debate in which she has previous form. Back in 2007 Ben Goldacre wrote about dubious evidence presented to the science and technology select committee that supported Dorries' anti-abortion views. Goldacre's article prompted Dorries to issue a bizarre call for an enquiry into how select committee evidence – which is supposed to be in the public domain – got into the public domain.

Over the years, Dorries has issued a number of ill-founded claims about abortion. They include the fairytale "hand of hope" story that she helped to propagate across the web; the incorrect assertion that the NHS didn't carry out abortions after 16 weeks; the claim that charity Marie Stopes International supported her policy views; an attempt to dismiss scientific studies that disagreed with her view as "an "insult to the intelligence of the public"; and some rather dubious interpretations of opinion polls that led a frustrated Dawn Primarolo, then minister of state for public health, to exclaim that "The Honorable Lady has asserted many things to be facts that are not."

Faced with Dorries' cavalier approach to science-based policy, it's hard for the rational voter to imagine a worse candidate for a position on the health select committee, but the Conservative Party has managed it, with a second seat on the committee handed to the extraordinary character of David Tredinnick, MP for the constituency of Bosworth, and possibly Narnia.

Tredinnick's passion for "healthcare research" landed him in trouble during the expenses scandal last year, in which he was caught claiming £700 for "computer software and consultancy to investigate whether astrology can be linked to alternative medicine."

Protesting his innocence, he explained: "There are aspects of this such as plant cycles, the tides, that are linked to the moon. That's a fact of life, and there is a school of thought that says the moon affects other things as well. It's easy to make fun of me over this but the fact is there is a link."

Indeed, Tredinnick's views go further. In a Commons debate on Complementary and Alternative Medicine last year he made the extraordinary claim that "... at certain phases of the moon there are more accidents. Surgeons will not operate because blood clotting is not effective." One wonders if Tredinnick wraps himself in wool and plaster at every full moon, lest a stray paper cut cause his blood to drain completely from his body.

Tredinnick is also a passionate advocate of homeopathy, and has filed a string of Early Day Motions in an effort to raise support for magical homeopathic remedies in parliament. EDMs are listed with their signatories on the internet, providing a handy guide to the identity of the more credulous and ill-informed MPs.

The latest of these EDMs came in a flurry of activity this week. First, the British Medical Association was called to account for daring to express the opinion – backed of course by last year's science and technology select committee report – that homeopathy should not be funded by the taxpayer.

Another three consisted of the MP and some of his more gullible colleagues welcoming three recent studies into the efficacy of homeopathy. These have already been drily amended by Liberal Democrat MP Julian Huppert, who tells me: "I tabled the amendments having analysed the methodology in the articles referred to; it turns out that none of them lead to his conclusions! In one case, one of the authors said 'I was not convinced it was a sound study' and asked to be removed as an author."

One of the studies has raised eyebrows as the research was apparently conducted at the M.D. Anderson Cancer Center, a prestigious Texan cancer research group. The centre's credibility will not be helped by its association with this work, although it appears that the lead author has since left the centre (my thanks to @medtek for that hot tip).

The study has been debunked by bloggers and scientists like Dr Rachel Dunlop and the blogger Orac, not least because the paper contains no statistical analysis of the significance of the results. In fact one of the authors left an extraordinary comment on Dunlop's blog, claiming that some results were removed from the paper, that she had asked not to be named as a co-author, and that there were clear alternative explanations for the results.

In spite of all this, the paper has been seized on by the homeopathy community, happy to ignore the flaws and the overwhelming weight of evidence against this 18th century relic. No evidence is too tenuous for homeopaths.

Naturally, there has been alarmed reaction to these appointments to the health select committee, but I suspect there's little really to worry about. Dorries may not even turn up, and Tredinnick is a figure unlikely to be taken seriously by policymakers. Still, questions should be asked about why a party that rejected alternative medicine before the election, and promised an evidence-based approach to public health has managed to place two such clearly unqualified people on this important Commons committee.

Martin Robbins writes for The Lay Scientist