Here's an article by Satoshi Kanazawa in Psychology Today that looks at an examples of generalizing and then stereotypes it:
The naturalistic fallacy, which was coined by the English philosopher George Edward Moore in the early 20th century though first identified much earlier by the Scottish philosopher David Hume, is the leap from is to ought – that is, the tendency to believe that what is natural is good; that what is, ought to be. For example, one might commit the error of the naturalist fallacy and say, “Because people are genetically different and endowed with different innate abilities and talents, they ought to be treated differently.”Interestingly, Kanazawa defends stereotyping in his book Why Beautiful People Have More Daughters. In the above he offers a stereotype of how political viewpoints attach to these fallacies.
The moralistic fallacy, coined by the Harvard microbiologist Bernard Davis in the 1970s, is the opposite of the naturalistic fallacy. It refers to the leap from ought to is, the claim that the way things should be is the way they are. This is the tendency to believe that what is good is natural; that what ought to be, is. For example, one might commit the error of the moralistic fallacy and say, “Because everybody ought to be treated equally, there are no innate genetic differences between people.” The science writer extraordinaire Matt Ridley calls it the reverse naturalistic fallacy.
Both are logical fallacies, and they get in the way of progress in science in general, and in evolutionary psychology in particular. However, as Ridley astutely points out, political conservatives are more likely to commit the naturalistic fallacy (“Nature designed men to be competitive and women to be nurturing, so women ought to stay home to take care of the children and leave politics to men”), while political liberals are equally likely to commit the moralistic fallacy (“The Western liberal democratic principles hold that men and women ought to be treated equally under the law, and therefore men and women are biologically identical and any study that demonstrates otherwise is a priori false”).
I'm not sure that the Kanazawa's stereotypes are right, but I would defend it as a tool to think about these things. In science you propose a hypothesis like this, examine its logical implications, and look for facts that support or conflict with this proposed "truth". So I'm happy to see him discuss this. I would be happy to see other opinions, arguments, and "facts" put forward to test the stereotype. Eventually I expect somebody will fit these political political stereotypes into a broader scientific theory. Of course Kanazawa will offer up evolutionary psychology as the place that this kind of theorizing will find a home. Maybe. Maybe not. But I'll enjoy the scientific discussion. I won't do what my feminist friends did in the 1980s, i.e. beat people about the ears for "generalizing".