Not all doctors or CEOs are men. Not all nurses are women. But you might think otherwise if you searched for these professions in Google images.

It turns out that there's a noticeable gender bias in the image search results for some jobs, according to a new study by researchers at the University of Washington and the University of Maryland. This underrepresentation of women in image search results actually affects people's ideas about professional gender ratios in the real world, the study found.

See for yourself...

This is what happened when I searched "nurse" in Google images:

This is what happened when I searched "doctor" in Google images:

This is what happened when I searched "CEO" in Google images:

That's all white men in that last one, in case you couldn't tell.

Though they're in the minority, there are some chief executives who are women and who are not white.

Researchers looked at the top 100 image search results for 45 different jobs. They then compared the gender breakdown of those results to actual gender data from the Bureau of Labor Statistics for each job.

It turns out that for some search terms, like "chief executive officer," the gender imbalance on Google is a lot worse than it is in real life. The study found that only 11 percent of the people shown in an image search for "chief executive officer" were women, while BLS data indicates that 27 percent of CEOs are women. Similarly, a search for telemarketers showed 64 percent women, even though in reality it's about a 50-50 gender split. Nearly 60 percent of bartenders are female, but in the image search results, only 23 percent were.

Not all jobs demonstrated such a gulf between search results and reality. But women were slightly underrepresented on average across all jobs the researchers looked at.

I was actually surprised at how good the image search results were, just in terms of numbers, said Matt Kay, a co-author of the study. They might slightly underrepresent women and they might slightly exaggerate gender stereotypes, but its not going to be totally divorced from reality.

And try searching a term like "female construction worker." (According to BLS data, 2.9 percent of construction workers are women.)

A number of the top hits depicting women as construction workers are models in skimpy little costumes with a hard hat posing suggestively on a jackhammer, said Cynthia Matuszek, a co-author of the study. "You get things that nobody would take as professional."

Google image search, like Google's many other search tools, mines the Web for content based on algorithms that are designed to show you the results it thinks you'd most want to see. Google's searches take into account a number of factors, like keywords, timeliness of the content, where you're searching from and PageRank , which is Google's way of analyzing how important a page on the Internet is. Google declined to comment about the study's findings.

The sad thing is, the gender biases displayed in search actually do have an effect on how people perceive gender breakdowns in the real world, according to the study. After being shown skewed image results for a certain occupation, study participants did report a slight change in their perceptions of how male-dominated a field was.

Of course, none of this is exactly Google's fault. Google is a reflection of what's on the Internet. You can also see similar search results on Yahoo and Bing.

But the researchers suggested that search engine designers could actually use these study results to develop algorithms that would help work against gender stereotypes.

Our hope is that this will become a question that designers of search engines might actually ask, said Sean Munson, another co-author of the study. They may come to a range of conclusions, but I would feel better if people are at least aware of the consequences and are making conscious choices around them.