While an MP he stood on the Science and Technology Select Committee.
Stewart was on the committee of the 2010 Science and Technology Committee "Evidence Check" report on Homeopathy. The final report was extremely critical of the use of homeopathy within the NHS. However, skeptical blogger Gimpy suggested that Stewart tried to "water down" the report. In the formal minutes it is revealed that Stewart put forward a proposal that the report had gone outside its terms of reference, and that instead of continuing to publish the report, they should "write to the Government to call on it to fund a rigorous research programme into homeopathy".
In May 2008 in the abortion amendments to the Human Fertilisation and Embryology Bill (now Act), Ian Stewart voted to keep the current time limit of 24 weeks in line with the scientific and medical consensus.
Ian Stewart seconded Early Day Motion 377 noting the achievements of Charles Darwin, and calling for Darwin's birthday to be designated a public holiday to honour "one of the fathers of modern science and one of Britain's greatest, if not the greatest, scientific minds."
In February 2010, Ian Stewart signed Early Day Motion 524: Recognising Climate Change which states that "this House agrees that climate change is happening and is man-made" and calls this statement a "fact, which has the support of the overwhelming majority of the scientific community".
Libel Law Reform
In March 2010, Ian Stewart signed the amended Early Day Motion 423A1 calling for a reform of the English libel law. The motion noted that human rights activists, scientists, writers and journalists are currently prevented from publishing, and the public prevented from reading, matters of strong public interest due to the chilling effect of the law. The amended version added a statement of the belief that "libel laws discriminate against average and low paid people when victims of defamatory comment in the pages of national publications".