I don't think that is really very true at all. I used to think so (that belief that all men are "like dogs" because of testosterone), but in the nearly two years since coming to this and other poly forums, it has surprised me how many women talk about their male partners having very low sex drives, or at least, lower sex drives than they do. In comparison, it seems a lot less men talk about their female partners having lower sex drives. Probably any stereotype in this area is bound up in social morés.
I meant it's true from a statistical standpoint, which is why I said it's meaningless when talking about individuals. It's a misapplication of statistics.
Let's say that someone invented some sort of scanner that could quantify and measure one's sex drive. (I'll also name the sex drive unit of measurement "Ron Jeremy Units [RJUs] because that amuses me.) This device is then used to scan 10,000 men and 10,000 women and the results are analyzed. The average for women would be something like 95 RJUs and the average for men 105 RJUs. Meaning, on average, men have a higher sex drive.
Things like this have some purpose when doing science, but are pretty much irrelevant for practical purposes. From the above fake study, the histogram of the results would look something like this:
Yes, it shows that men have a higher sex drive than average, but it also shows that there's plenty of overlap. Most people would fall in the purple area. When taken as a whole the sex drive of men is higher, but there's so little difference between the two groups that it serves no practical purpose.
In actual studies done on this subject the bell curves are a little further apart, but it shows a large area of overlap as well. The Ron Jeremy Scanner doesn't actually exist, so surveys have to be used. In surveys like this men tend to overstate things and women understate things. My made up graph is probably closer to reality than the actual surveys show, but there's no way to determine that scientifically.
The problem is that people take surveys like this and interpret them without understanding them. They see the blue and red areas, say "men want sex more than women," and then they're done with it. What the study actually shows is that there isn't a significant difference between men and women when it comes to sex drive.
Misinterpreting statistics causes other problems as well. I'm sure everyone has heard at some point "Men hit their sexual peak at 19 and women at 35." It's actually crap. The study that "fact" is from didn't take into account that men around their early 20s are the most full of crap when talking about their sexual experiences and that women in their 30s are more comfortable talking about theirs than are younger women.
Also, a study I conducted just now shows that I put a lot of effort into going off on tangents when posting on forums.