your first response should be "which studies? Show me."

90% of the time, people are either making crap up; have been told by people making crap up; lying about actually reading any studies or somewhere along the line someone didn't understand the research.

of the 10% that's left, half of the research was done in specific conditions under which you can only suggest a correlation to the population as a whole.

And that last 5%? How much of it is in 100% agreement with other literature?

It's like the scriptures. . .if your wife cheats on you and you want to justify stoning her, you find a passage from the old testament. If you cheat on your wife and want her to forgive you, you hit up the story of how Jesus responds to the woman taken in adultery.