Perhaps nothing illustrates the sweeping changes in PR these past decades than the shift in gender balance at firms nationwide. Yet while women are increasingly joining our ranks, especially at the junior and mid-levels, the question remains: Has the female-to-male ratio changed at the top?

What's more: How are women in communications rising through the ranks these days? What are the secrets of their success—and how are they bucking stereotypes? Are they mentoring their female staff to do the same? And what do they think the PR gender mix will look like in the future?

For the answers and their career advice — and in conjunction with next week's Council member dinner with Pattie Sellers, the Chair of Fortune's Most Powerful Women Summit — we interviewed nearly a dozen powerful women in PR, many of them industry veterans who actually helped shape the more balanced public relations field we enjoy today. Responses of six of these luminaries—Christine Barney, Margery Kraus, Melissa Waggener Zorkin, Donna Imperato, Margaret Booth and MaryLee Sachs—follow here in the first of a two-part special focus:

Christine Barney CEO rbb Public Relations

Little has changed at the top of the agency world. Over the last two decades, women have risen up the ranks to practice leaders and office leaders, but are still not appropriately represented in the C-suite of the largest agencies. However, many of the up and coming independent firms are led by women entrepreneurs who have chosen to create their own path to success.

I've seen much more change on the client slide where there are a greater proportion of women holding the top titles. The caveat is that when the corporate communications and HR directors are usually the only women on a board, the feminization of those functions is further reinforced.

The evidence indicates the future of PR will be built on the X chromosome. There was not one male among the last three university PR classes who toured rbb. A recent job posting for a junior position saw the ratios of female to male applicants at 14 to 1. Most of the male practitioners we see are in investor relations, public affairs and crisis work. As far as general PR, the industry is now firmly in the category of teachers and nurses—defined as a career primarily for women.

Thoughtful, strategic planning is the key to any effort to diversify employees. If men are not to be found in the university PR setting, build bridges with business, MBA and journalism programs. The work-life balance equation is an asset to both sexes. Public relations can deliver flexibility like very few other professions, and the millenniums of both genders can be wooed to the profession with the right messages, perks and salary.

My advice to women in communications:

• Dress for the job you want. You can still be casual and professional but too many younger women dress for college, not work. Present a professional look and you instill confidence in clients and colleagues that much faster.
• Leave the "‘inferiority complex" behind. Regardless of age, your viewpoints and ideas are welcome and valid. Playing the wallflower means less opportunity and less learning.
• Blend. The key to work-life balance is not to force all your working into Monday-Friday and all your living on weekends. Both PR and your personal life are 24/7. Blend work and personal needs by doing what needs to be done when it needs to be done rather than constrict your planning within artificial parameters.

The secret to success is to find what motivates you and feed that passion. My entrée into PR came from a desire to learn. I need the challenge of exploring new ideas, industries and opportunities. When complacency rears its ugly head, passion to learn kicks in and processes are reinvented, fresh connections made and new skill sets added.

Margery Kraus Chair, President and CEO APCO Worldwide

I don't know if there were more than one or two women leading global companies when I first started, but there are increasingly fewer impediments for women reaching the higher levels. When I go to meetings, I'm no longer the only woman in the room. I'm just as likely to sit across from a woman senior executive on the client side as a man now. It's a positive trend.

My hope for the future would be that gender wouldn't even be a question. It would be irrelevant. It would be all about whether people were qualified to run the organization. Competence trumps gender—and that's not just being aspirational. It's the way things are now.

That is as it should be. This is a business of teams and if you're going to have teams, you have to recognize that men and women bring different skills and perspectives. So, we should continue to create diversity that is reflective of the clients and markets we serve. When you had 15% women in PR, we weren't doing a service to the client. The same goes if it's only 15% men. Success for firms is all about finding a balance and being smart about using everybody's skills to the best effect for client. So, regardless of gender—there is a role for everybody.

My advice to women entering the profession is this:

• Seek flexible work environments. Men are struggling with live-work balance issues, just like women. But women are typically the caregivers—so it can be harder to achieve that balance. That is why we all need to be thinking more about flexible work environments. For example, we have emergency childcare in our office.
• Recognize that certain biases remain. I was part of panel on gender parity at the World Economic Forum, and there is a lot of research that shows that if men and women deal with lingering perceptions of women having to leave work to take care of the child. If the woman doesn't take that time away, she's seen negatively. So, there are biases that still will take a long time to get over.
• Embrace stretch opportunities. Don't be risk-averse. In businesses where there is a difference in gender and there is a stretch opportunity available, the man will traditionally say, "I'll go for it." The woman traditionally might say, "I've never done that before." So, be honest—but stretch yourself, and don't be afraid to take advantage of opportunities when they come up. In addition: Do the very best job you can with what you have and do not worry about your five year plan. Every job is a stepping stone to another experience. So, don't look so far ahead that you're not doing well at what you're currently. Get noticed by doing great work. And finally, love your work. If you don't have passion for what you're doing, find another job. This work is too hard to do if they're just a "job."

Melissa Waggener Zorkin CEO, President and Founder Waggener Edstrom

I haven't kept track of the ratio between men and women; I just track talent. You could say Waggener Edstrom Worldwide is unique in that those two names on the door are … female. My incredible partner, Pam Edstrom, has been with me for 25 years. Regarding our people, I do know that there have been times when there are way more women in meetings, and also times when there are more men. In our senior management group meeting last week, I counted: It was precisely a 50/50 split.

This industry doesn't look at gender but rather attracts, nurtures and promotes those who can provide business insight to their clients, understand influence and the power of storytelling, and drive business results. People who come to mind are Kelly Groehler of Best Buy, Frank Shaw at Microsoft, Dave Samson at Chevron and Scott Monty of Ford. These are passionate people who lead the dramatic changes going on in our industry and are taking new approaches and using new tools and channels.

When I look across the industry today I see how the communications landscape has changed and continues to morph. Virtually anyone has the ability to be an influencer and have a voice. The ability to leverage the power of content in driving audience engagement and show value in every dollar spent on communications is the key consideration for success.

We're going to see people join our industry who focus on the power of true business consulting to the C-suite, understand the critical nature of data analysis to help solve business problems, and know the value of strong storytelling and the extension of influence to engage key stakeholders around the globe. It has never been about gender; it has always been about providing value to clients. The mix is not important at all, other than for us to be sure both women and men are getting an equal chance to come into our industry and have opportunities to do great work and grow their careers.

What I see is a tremendous influx of talented people focused on the power of influence—both men and women. We're going to see people who traditionally may not have thought of a career in communications joining our ranks. This will be driven by both the demand for a more diverse array of talent to address the increasingly complex set of business challenges and opportunities and their own interest in the evolving nature of communications. The PR industry continues to expand its focus to include deeper data analysis, design, content development and measurement solutions. To me, this results in a very balanced mix of talented people—all driving a better business outcome for clients.

In terms of advice, I would say the same thing to younger women as to men:

• Do something you love. The balance will come more naturally. I love my job—I always have. Doing something I love pulls me through when there is work overload. Another secret is to focus on what really matters during the day. Every day, set a goal and work toward it. Work on the important and not the urgent. Rely on the people around you. Tell them what they can count on and always keep those commitments. Also, set expectations when you can't do something. Tell people upfront. I am quite grateful because, as an entrepreneur, I started a company that is still the place I want to be. And I am lucky that 800 people feel the same way at Waggener Edstrom.
• Pursue on-the-job training. I am a firm believer in on-the-job training. I participate in programs that include welcoming junior people to be co-CEO for the day and, one of my favorites, the Leadership Forum. The Leadership Forum is a manager-nominated group of up-and-comers with whom we spend focused time, helping them grow as a group and as individuals. It is one of my favorite priorities. I learn from them as much as they learn from me.
• Work with mentors. A common theme when I talk about leadership is the need to get the right person in the right place at the right time. As such, when I mentor people I always strive to understand their unique value, contribution and aspirations, and then think through what it will take to help them get the most out of their talents and match that with what the agency needs and can offer them.

Donna Imperato CEO Cohn & Wolfe

I don't think there's been a significant shift in the female/male balance. And it hasn't changed at the top. The smaller boutiques have always had more women leaders than the larger firms. But at the top 10 or 15 PR firms, there will only be Cohn & Wolfe and APCO with a female CEO after Marcia Silverman retires this year. A few years ago, we also had Helen Ostrowski in the mix, so the trend at the top is going in the wrong direction.

I believe this will change after the current generation of male leaders retires. The younger generation is much more open to female leadership. Outside our industry, we've seen an increase in women CEOs and other women leaders. It will eventually happen in PR. I also believe that the transformation of our profession in the digital age will bring more and more males into our business at the more junior levels, getting us the balance that we desire in our industry.

My advice to women in PR:

• Don't expect a "9 to 5" career. Younger women need to work extra hard to rise to the top in our profession. I know this will be controversial, but I don't believe that you can rise to the top while working part-time or needing to leave the office at 5 pm.
• Strive for quality time. However, you can do well and hold important positions while balancing your home life. Many women leaders with families, like me, find a way to make it work. But I wouldn't call it balance! I work late nights and weekends more often than not. But I go home, take care of the family and do my work later in the evening. I travel often and don't see my kids as often as I'd like. But every amount of time with the family is quality time. It's a way of life that works well for all of us. Working hard, staying focused and managing to find a balance that works for you is the key to success.
  

Margaret Booth President M Booth & Associates

I think that if you started out as entrepreneur in this business and have been able to build it, then there's no issue: You're at the top. You've had to struggle where you are. But the women operating in big holding companies and giants have a harder row to how.

There are more of them coming along, but the Helen Ostrowski's and Marsha Silverman's—they just retired—were really great examples of women who made it to the top at a time when there were fewer women there. But other women are making their way now—so I think the path for women is wider today than it was. As you move forward, you will see more women at the top. Gail Heimann, for example, is a major player at Weber. Donna Imperato is at the top of her game. And Margery Kraus is someone who built a $100 million business and certainly is no slouch. Other brilliant women in PR include Aedhmar Hynes of Text 100. She is someone who has made a huge impact in the technology driven space, which is very male dominated. She is a real role model and has built a spectacular company around the globe.

These women are making their way and setting great examples for women who are mid-career. As time goes on, there will be more women like that. If you look at the lower end of things, there aren't as many men in the lower ranks than there used to be. Interesting enough, we rep the Wharton School, our longest-standing client—and their incoming freshman MBA class for the first time is 40 percent women. So, I think a lot of times when you get to the top of large holding companies, a lot of the men may have had more business and managerial experience in the past—but that figure portends well for women as CEOs beyond communications moving forward. You'll see more people like Beth Comstock, who is now SVP and CMO at GE. Others include Ruby Anik, SVP of brand marketing, and Merianne Roth, brand marketing and publicity director—both at J.C. Penney. Another woman in communications at J.C. Penney is Darcie Brossart, their VP of corporate communications.

My advice to other women coming up in PR, on both the firm and client sides, is this:

• Internalize confidence. Feel very confident in yourself and abilities.
• Move beyond gender. Forget that you're a woman and just do a damn good job.
• Lead and motivate. Be extremely determined and very aware of your surroundings. By that I mean that there is a functional and emotional side to operating well. It's one thing to go to work and do well in your job—and it's another thing entirely to understand what others around you are dealing with and being a part of a productive, creative, growing team. The latter requires engagement, understanding and being a motivator. That's true leadership—not just demanding the end product. Give people a little slack and let them know that you understand that life isn't always perfect. I think you can get great contributions from anywhere if you can be real and if you can inspire people by recognizing that they have lives beyond the tasks they face. The mere fact that you recognize that will get them to go the extra mile for you.

MaryLee Sachs Chairman US Hill & Knowlton

I don't think the gender balance has significantly shifted. There are a few more women in the top ranks, but it will take a long time to redress the balance. One of the issues has been that there are more men in the corporate or public affairs side of our business—rather than consumer marketing, and agency leaders have traditionally come from that side of the business, rightly or wrongly. I would like to think that PR is being taken more seriously among our marketing clients, and as consumer marketing PR is elevated in importance with the CMO, so will it be within its own business.

Moving forward, I would like to see the female/male mix relatively equitable, reflective of the U.S. population. If we are relating to publics, it should be. I believe the same thing as it relates to diversity in our business. My advice to women in PR:

• Recognize that live-work balance remains a challenge. It is incredibly difficult for younger women looking to have a family—or anyone, for that matter—to find work-life balance in our business. On the agency side, we are on call for our clients. On the client side, the news cycle is 24/7 and responses have to be fast if not immediate.
• Use technology to maximize flexibility. The advent of technology has helped considerably. Blackberries, smart phones, RSS feeds and social media inventions like Yammer are all handy helpers to accessing what you need when you're not at your desk. (I'm responding to you via wi-fi on my Virgin America flight to San Francisco!) But the quid pro quo is that we need to be flexible as well.

Editor's note: Watch for the second part in our "Powerful Women in PR" special focus in two weeks, where we'll feature the perspectives and secrets of success of Laura Tomasetti (360 Public Relations), GG Johnston (Johnston Wells), Kathy Obert (Edward Howard), Becky Powell-Schwartz (The Powell Group) and Jennifer Graham Clary (Burson Marsteller).