False balance

False balance, also bothsidesism, is a media bias in which journalists present an issue as being more balanced between opposing viewpoints than the evidence supports. Journalists may present evidence and arguments out of proportion to the actual evidence for each side, or may omit information that would establish one side's claims as baseless. False balance has been credited with spreading misinformation. 
False balance can sometimes originate from similar motives as sensationalism, where producers and editors may feel that a story portrayed as a contentious debate will be more commercially successful than a more accurate account of the issue. Unlike most other media biases, false balance may stem from an attempt to "avoid" bias; producers and editors may confuse treating competing views "fairly"—i.e., in proportion to their actual merits and significance—with treating them "equally", giving them equal time to present their views even when those views may be known beforehand to be based on false information.
Examples of false balance in reporting on science issues include the topics of man-made versus natural climate change, the health effects of tobacco, the alleged relation between thiomersal and autism and evolution versus intelligent design.
Examples.
Armenian Genocide.
Terrence Des Pres reported in 1986 that, "until recently the facts of the Armenian Genocide were thought to be certain beyond dispute" but, due to the geopolitical position of Turkey on the one hand, and an increasing tendency to treat each issue as a question with two equally legitimate sides, the facts were increasingly treated as something up for debate.
Climate change.
An example of false balance is the debate on global warming. Although the scientific community almost unanimously attributes a majority of the global warming since 1950 to the effects of the industrial revolution, there is a very small number, a few dozen scientists out of tens of thousands, who dispute the conclusion. Giving equal voice to scientists on both sides makes it seem like there is a serious disagreement within the scientific community, when in fact there is an overwhelming scientific consensus that anthropogenic global warming exists.
MMR vaccine controversy.
Observers have criticized the involvement of mass media in the controversy, what is known as "science by press conference", alleging that the media provided Andrew Wakefield's study with more credibility than it deserved. A March 2007 paper in "BMC Public Health" by Shona Hilton, Mark Petticrew, and Kate Hunt postulated that media reports on Wakefield's study had "created the misleading impression that the evidence for the link with autism was as substantial as the evidence against". Earlier papers in "Communication in Medicine" and "British Medical Journal" concluded that media reports provided a misleading picture of the level of support for Wakefield's hypothesis.