Google engineer James Damore famously suggested that there are few women in technology jobs because we're biologically unsuited for those rules. Now research from Stanford reveals a simpler explanation: Technology recruiters on college campuses subtly make it clear from the beginning that women aren't supposed to be in those jobs. That message may be delivered unintentionally and even unconsciously. But it's being heard loud and clear: Women with STEM (science, technology, engineering, or math) degrees are dramatically less likely to wind up in tech jobs than their male counterparts.

How is this message of unwelcome being delivered? To find out, Stanford sociology graduate student Alison Wynn and professor Shelley Correll led a team of researchers who attended 84 on-campus recruiting sessions for graduating STEM students over two years. What they witnessed should be enough to depress anyone who hopes to see greater gender parity in the high-tech world. Here's what students who attended the recruiting sessions learned about the companies that came calling:

Men give presentations; Women hand out raffle tickets.

Students were typically greeted by a female recruiter who handed out raffle tickets and directed attendees to a snack table at the back of the room. At the front of the room, one or several men would be setting up a projector or reviewing their notes. 

When the men began their presentation, they would introduce themselves and their engineering colleagues, but rarely the female recruiter. The few men who did reference the female recruiter often did so in an unhelpful way, such as one who told attendees to pass their raffle tickets to the "lovely ladies" in the back of the room. Another introduced a recruiter this way: "This is Kathy. She's really nice. She cries easily."

Men speak, women don't.

Some recruiting companies did send female engineers to the recruiting sessions. In most cases, these engineers did not participate in the presentations or Q&As. Those who were included in the presentations talked about "soft" topics such as company culture, rather than the "hard" tech topics covered by the men.

During the Q&A sessions, which varied widely in length and formality, men asked most of the questions, and men gave most or all the answers, even when there was a female engineer on hand. The researchers described one Q&A session where the lone female engineer attempted to answer questions but was repeatedly cut off by her male colleagues.

Forget work-life balance.

Many of the presenters talked about the perks their companies offered, such as free food, dry cleaning, in one case even a chiropractor--great because you could get an adjustment and be back at your desk in a few minutes. In every case, the subtext was clear: Expect to spend most of your life at work.

Sometimes it wasn't just subtext. Several startup companies boasted of the long hours their employees put in. One suggested students visit the company at midnight or 2 a.m.--because there would always be employees there. 

Research has shown that even in households with female breadwinners, women still perform most of the housework and child-rearing. Given that reality, it's also unsurprising that women have proved more reluctant than men to join a company that promises they'll have no time away from work.

It will be like a frat house.

Many of the companies--again, especially the startups--seemed eager to let potential recruits know that working at their company was a lot like hanging out at a fraternity. There were plenty of Star Trek posters, video games, and foosball tables in evidence. Recruits were promised beer fridges and given beer-related swag. Profanity and sexual innuendo were woven into presentations, especially those from startups. (Larger, well-established companies are likelier to have things like diversity training.) 

As the researchers point out, plenty of women love Star Trek (I'm a fan!), video games, and beer. But it's emblematic of Silicon Valley's "brogrammer" culture that's been shown to drive women who do get technology jobs into leaving those jobs quickly.

It doesn't have to be this way.

In fact, it should already not be this way in an economy where nearly every company worries about the talent wars and the difficulty of hiring needed tech talent. While 40 percent of male graduates with STEM degrees work in STEM-related jobs, only 26 percent of female STEM graduates do so. That suggests that for every two female engineers employers hire, they're losing one to some other profession. This report on what goes on at recruiting sessions provides some excellent clues as to why that's happening.

But it wasn't all bad at every recruiting session. The researchers reported that some companies did some things better--explaining how their technologies help people, or emphasizing work-life balance with statements like "It's a marathon, not a sprint," and "Family first." 

It worked. The researchers observed that in recruiting sessions where such things took place, female students seemed more engaged. They were about twice as likely to ask questions in these sessions as they were in the more brogrammer-flavored ones. There is, of course, a big journey between asking a question during a recruiting session and actually applying for a job. But women who sat silent during the sessions, or--as often happened--left before the end are highly unlikely to make that journey.

You would think a company smart enough to put serious resources into recruiting would be smart enough to avoid alienating qualified female graduates from the moment they walk in the door. Logically, companies that make female job candidates feel welcomed and respected should have a hiring advantage, and therefore a competitive advantage, over companies that don't.

I wonder how long it will take them to figure that out.