what is this fallacy?

[hyksos]

What is the formal name of the fallacy that goes, "All serial killers drank water, therefore water might cause your kid to be a serial killer" ?

[hyksos]

Hmm.. I think I may have found it already.

http://en.wikipedia.org/wiki/Association_fallacy

[Braininvat]

It's also similar to "post hoc ergo propter hoc." ( which would be - the murderer drank water before killing, therefore water consumption causes homicidal acts....) The association fallacy arises from multiple uses of the propter hoc fallacy.

[hyksos]

Braininvat, when doing experiments on lab mice, they will try to have two groups, where one is the 'control', and they carefully make sure both groups of mice are eating the same things and in the same environment. This is specifically done because of this fallacy.

[Scott Mayers]

What is the formal name of the fallacy that goes, "All serial killers drank water, therefore water might cause your kid to be a serial killer" ?

Technically, there is no error with the word "might" in there. It would be odd for one to assert though without context. This might be used to compare an equal kind of argument another might be trying to make as though some consequent is more relevant than it is.

One might argue: "Given that in some study of inmates incarcerated in some large prison All serial killers are Male, it suggests that being male is a likely sufficient cause to become a serial killer."

This kind of argument is made a lot politically because it is not technically illogical but has unclear quantifiers or appropriate ones that rhetorically suggest something more than it is. It is an error of irrelevance for being insufficient as a justification. It might be classed as an error of missing evidence.

A feminist might use this, for instance, to suggest why they specifically believe it only relevant to have laws to protect women's rights by imposing stronger penalties against men as a class in some law being proposed. While it doesn't deny that women too could be serial killers, the rhetorical defense of their position implies women are either never serial killers or are too insignificant to be concerned about.

So to counter, you might use your initial statement to show the fault by an exaggeration for contrast.