Last year’s massacre at Sandy Hook Elementary School in Connecticut was beyond tragic—and there have been more school shootings since then. In response, lawmakers in Washington have launched a game of political football.

But this isn’t about political wrangling around gun control; it’s about guns in places like schools and worksites. In addition to school shootings, there have been many fatalities caused by people turning their guns on colleagues at work.

According to the U.S. Bureau of Labor Statistics, about 78 percent of the approximately 518 workplace homicides in 2011 were gun-related.

In just the last few months of 2012, there were several tragic examples:

In September, a Minneapolis man who had been discharged opened fire in the company break room, killing five former co-workers before committing suicide.

The term “boys’ club” refers to the unofficial and often impenetrable group of men—usually white men—in an organization or department who have effective control and power. Being part of or having access to the club often is critical to making the right connections to advance within the organization.

Because these groups often form covertly, and sometimes as a result of unconscious rather than conscious bias, the membership does not always correspond to the organizational chart. Moreover, top executives often deny the existence of an exclusionary club. I have never seen a “formal” boys’ club, yet I would be foolish to deny that it exists at some organizations.

When it comes to determining the scope of a boys’ club, official positions may be relevant but not determinative. I have seen organizations with gender equity at the top, but the real power is held by men. Conversely, I have also seen organizational charts where most power positions are held by those with Y chromosomes, but I didn’t think there was any gender bias in general or a boys’ club in particular.

Why are these clubs present in some companies? And how do we eradicate them?

I do not pretend to have all the answers, but I do have some thoughts to help HR professionals move toward equal employment opportunity (EEO).

Bias in Your Backyard

Sex discrimination, including gender stereotyping, is illegal. More than that, it is bad business.

Ensuring gender equality is a business imperative in terms of attracting, retaining and advancing talent that goes beyond the legal imperative. We exclude women or any other group at our peril.

You may be thinking, “Of course. This is hardly news.”

Most executives outside of HR would agree. They understand the business drivers mandating diversity and inclusion.

Still, most do not see the bias in their backyards. Don’t assume that everyone understands the business costs of bias.

Why Boys’ Clubs Exist

There are many reasons an organization or a silo within may have a boys’ club.

The first is what the U.S. Equal Employment Opportunity Commission calls “like-me” bias: the human tendency to be more comfortable with those who are like you.

“I don’t discriminate,” says the executive. But he socializes with, plays golf with and feels more comfortable among those who look like him.

Does this risk exist in an organization where women are in control? You bet. Executives in these organizations face the same risk of like-me bias to the detriment of those with Y chromosomes.

Boys’ clubs do not justify girls’ clubs, legally or morally. Power clubs that exclude men are also bad business.

Like-me bias is usually the product of unconscious affinity toward similarity. Sometimes, however, conscious considerations contribute to a boys’ club.

These considerations may be well-intentioned. We live in a painfully litigious world. One misstatement may later be used as evidence of bias, even if the statement was made out of awkwardness as opposed to malice.

In the “gotcha” world of employment litigation, leaders appropriately want to avoid saying the wrong thing. They sometimes inappropriately avoid people they fear may perceive their words in a negative light. But you can’t avoid bias claims by avoiding those who are different from you. That’s called bias.

There is more room for human error in a diverse group. While that may explain, in part, why some clubs exist, it does not justify their existence.

In addition, members of boys’ clubs often justify their activities as being primarily social. Work is hard and seems to be getting harder. In the 1970s, Spiral Starecase sang, “I love you more today than yesterday but not as much as tomorrow.” The theme song for today’s business world could be “I expect more from you today than yesterday but not as much as tomorrow.” So, when people work hard, they may want to play hard, too.

In mixed-gender groups, the sexist “joke” is more likely to be costly, and the appropriateness of going to strip clubs is more likely to be challenged.

So we move from the ’70s to the ’80s, when Cyndi Lauper sang “Girls Just Want to Have Fun.” Today, the boys who just want to have fun fear that the price tag may be too high if women are included in certain activities, so some don’t include them.

Dismantle Boys’ Clubs

Just so there is no confusion: Even in male groups, the sexist jokes are not funny and the strip clubs are offensive. There are many men—I am one of them—who say so, but fewer men than women will bring claims based on them.

There is no magic bullet to dismantling these clubs, but here are 10 recommendations for your consideration:

• Educate executives about the potential for the existence of a boys’ club and the business costs of such a group. You cannot stress enough the costs of excluding women from the inner circle. It is not only about the talent women bring but about the fact that men who operate in diverse groups tend to be better employees.
• Make sure your job descriptions for leadership positions do not inadvertently exclude women. Don’t include a minimum number of years of experience that is not necessary for the position and that women historically have been denied the opportunity to achieve. For example, for an operations position, if the number of years of experience required is unnecessarily high, it may perpetuate bias engaged in by prior employers. Do you really need someone with 15 years of experience? Is 10 enough? At least ask the question.
• Open the promotion process so that when senior positions become available, credentials, not connections, matter. Leadership roles too often are willed to the next in line, and that person often looks like his predecessor in terms of demographics. So, as a general rule, post the opening.
• Give a “plus” to differences in experiences, perspectives and leadership styles as part of decision-making. When we focus on these aspects of diversity, we increase EEO diversity. However, do not give gender a plus. Under Title VII of the Civil Rights Act of 1964, employers probably cannot consider gender a plus unless there is a remedial purpose. For private-sector employers, that means either an admission of prior discrimination or proof of a “manifest imbalance” in traditionally segregated positions. For public-sector employers, only an admission of previous discrimination will do.
• Consider affinity groups that focus on gender issues so that women can learn from one another and develop career strategies. But be careful: As a practical matter, an affinity group should be a launching pad, not a landing pad. As a legal matter, if you support an affinity group for women, do you have to do the same for men? Here comes the annoying lawyerism: “It depends.” If the affinity group is supported by the employer so that it would be considered a term or condition of employment, employers cannot discriminate based on gender. The same would be true of race. Develop EEO-neutral criteria for affinity groups, and allow any groups to argue that they meet them. For example, any group that wants employer support should have to present the business case for the need and a plan for how the group will expand the business. In female-dominated professions, a male affinity group may meet the criteria.
• Develop a formal mentoring program. In the absence of a formal program, like-me mentoring often benefits people who are like those at the top. Be careful that any formal mentoring program does not do the same. Many formal programs gender-match. If people at the top are predominantly male, doesn’t that mean that men will benefit more? Moreover, isn’t it misguided to suggest that men cannot mentor women or vice versa? And doesn’t gender-matching, when it comes to mentoring, deprive men of power the opportunity to learn of barriers that they did not know existed? When there is cross-gender mentoring, mentors often learn as much as they impart.
• Pay attention to micro-inequities that collectively may result in macro-exclusions. Leaders need to think about with whom they have lunch, go for drinks, attend sporting events and connect through social networking. We all know it is in the context of these informal interactions that relationships are strengthened and information is shared. These informal interactions may be the visible and discoverable manifestations of a boys’ club.
• Diversify organizational social events so that many interests are covered. Mix things up. Of course, not all women like to shop for shoes, and some men do. But I suspect more women do than men. (I once was on a panel on gender bias in the legal profession, and the only issue on which there was a good-natured gender divide was shoes. I still think two pairs is enough: one formal and one informal.) In any event, can you imagine if your only company-sponsored social events involved shoe shopping? Are male-dominated sporting events different? By offering diverse activities, you will maximize inclusion and have some fun, too. How do you know what might be of interest? Ask.
• Focus on alcohol. Why? Many boys’ clubs have as charter members Jack Daniels, Jim Beam and Old Grand-Dad. Drinking buddies and membership in boys’ clubs often overlap. That does not mean women don’t drink socially or even excessively. But often the boys’ clubhouse is a neighborhood bar.
• Don’t deceive yourself into believing that only cave dwellers engage in sexual harassment. While we have made progress as a society, sexual harassment is alive and well. Sexist jokes, verbal innuendo, visits to strip clubs—sometimes these missteps result in a claim. Just as bad, they effectively push women away.

Some women will stay with your organization but opt out of the social events where inappropriate behaviors occur. Marginalized, these employees don’t realize their full potential. Worse, they may take their talent and outside relationships to a more inclusive employer. Inappropriate conduct may not be severe or pervasive enough to create a hostile work environment, but it may create a boys’ club when women choose not to go along to get along, a choice no one should ever have to make.

The author, a partner with Duane Morris in Philadelphia and managing principal of the Duane Morris Institute, focuses on counseling, training and strategic planning to minimize litigation and unionization.