The HPV study makes sense actually (caveat, I haven't read it). HPV is a highly contagious cancer-causing virus. What the study was probably trying to do is to figure out the risk factors for contracting this virus. Oral sex makes sense as a candidate and because marijuana is usually shared in a way that tobacco isn't, it makes sense, too. I bet randomly kissing strangers would be a risk factor, too, if it was something that a significant fraction of the population did.

(Of course, the media rephrases and reinterprets as needed.)

Also, that stock market = hormones article is a HUGE stretch from the original. The original was an illustration USING traders that levels of certain hormones affect risk-taking behavior in a nice quantifiable setting. At best it can be said that your ability to manage your own portfolio on a given day is hormone dependent. The collective behavior of the stock market can NOT be generalized from this even if it applied to everyone as part of the way the study was constructed was to normalize each individual's hormone levels.

It's like saying that the number of words you type in a given LJ post is correlated with how much risk you're willing to take when driving to work. Ergo, the number of road accidents in a given year is entirely caused by LJ posting.