(FORTUNE Small Business) – While there's nothing magical about $1 million in sales, that number has taken on symbolic importance to small-business owners --both male and female--who desire to grow big. Yet why is it that females lag behind males as members of the million-dollar club?

Is it a lack of desire to run a large operation, spawned by the realities of balancing work and family? Discrimination by the equity investors who could fuel the companies' growth? Exclusion from the old-boy network that opens the door to government and corporate contracts for men? Or is it something else altogether? And how is the playing field shifting?

To explore those questions and more, Fortune Small Business's editorial director, Brian Dumaine, and senior editor Elaine Pofeldt convened six women (and a token male) who are on the front lines of new-business creation, from venture capitalists to small-business bankers to veteran entrepreneurs.

Here are their observations.

FSB: Why are so few of the businesses with more than $1 million in annual sales owned by women?

Jennifer Fonstad, managing director of the venture capital firm Draper Fisher Jurvetson in Menlo Park, Calif. First off, I think there are many more women business owners than the statistics show. Those numbers are based on women owning 51% of the business. In the venture world the entrepreneur who founds the business may typically own only 10% to 25% of the company. Often a woman is on a team of men who are co-founders.

FSB: But still, the number is small. Is juggling work and family holding women entrepreneurs back from building big companies?

Marsha Firestone, president and founder of Women Presidents' Organization, a New York City group for women running businesses with annual sales of more than $2 million. No, I think it's the opposite. A lot of women want to be in the entrepreneurial world when they have a family because they can control their time, particularly women who have been in a corporate environment. If they want to work in the middle of the night, they'll work in the middle of the night and go to the school play. I know a woman with two children under the age of 10 who doubled her revenues in the past year. She works in the middle of the night. It is a high-growth business.

Julie Garella, senior VP and director of business development for Citigroup Capital Strategies. That's right. Just because you're running a lifestyle business, it doesn't mean that you're small. You can have a $50 million business that you're running as a lifestyle company.

Michael Greeley, managing general partner of the venture capital firm IDG Ventures, in Boston. He is one of the leaders of Springboard Venture Forum, a program dedicated to improving women's access to equity markets. We don't live in a 9-to-5 world anymore. Because of the pervasiveness of technology, you can have a personal life co-exist with a very successful business.

Maria Coyne, executive vice president of KeyBank, based in Cleveland, and head of Key4Women, the company's woman-owned business banking program. I see it differently. Among some women entrepreneurs, there is a conscious decision to keep business a certain size or to focus in a certain way to take into account other things that are going on in their lives. I have a client who had a chance to grow from half a million in revenue and didn't like her life very much. She decided not to scale her business up, and today she does about $230,000, and that's where she'll stay. It was a lifestyle choice.

Susan Pinkwater, founder of the Bee's Knees, a creative arts center in Montclair, N.J., and founder of BBDO's digital ad agency, @tmosphere. My sense is that women face a barrier, whether people want to say it or not. I run a business and have little kids. I'm up in the middle of the night feeding babies and going to work with wipes coming out of my pocket. I can do it. Women absolutely can do it. But you are working harder than the guy next to you. He gets to sleep all night.

FSB: Does discrimination by VCs and other investors block women's progress?

Greeley: The old guard who are largely retired or are retiring are probably guilty of subtle bias. After the bursting of the bubble, a lot of people replaced them who are much more responsive. I don't think the problem is so much venture capitalists, but our institutions. Are the academic centers, the hospital centers, the corporations creating a pool of talent that has adequate representation of women? For a woman coming back to a working career, it may be easier to open a retail store than to take a new technology and build it. It's easier for a woman entrepreneur to get into industries where a business might not scale as rapidly--more retail or service-oriented businesses. Those are businesses that tend not to attract venture capital and have a particularly high failure rate.

Garella: What's different today is that there is a lot of private-equity capital out there looking for more traditional types of businesses, that is looking to buy out management teams, to back companies that have long operating histories and want to grow quickly. The private-equity people set a 25% minimum annual rate of return on this investment. But in my experience, that type of capital is gender-blind.

FSB: Does fear of losing control of a business stop women--more than men--from seeking outside investors who can help their business grow?

Firestone: Women entrepreneurs are getting certain benefits by having control, and they don't want to give it up--and I don't blame them.

Greeley: The younger generation of women appreciate that they'll most likely have half-a-dozen careers. They also are confident that they'll be able to get back into the game once they sell their company. Women in the older generation may hold on to their companies longer because they're afraid that once they sell them, it will be hard to get back into the thick of things and start a new business.

Pamela O'Rourke, founder of the fast-growing high-tech consulting firm Icon Information Consultants in Houston. If someone wants to buy my company, I will have to sign a noncompete agreement for five years, which I wouldn't want to do. I want my company to reach at least $100 million in revenues and be in 50 states. Right now we're in 40 states, with $42 million in sales. I'm not satisfied with that. I want to be No. 1.

FSB: Women entrepreneurs are winning only 4% of the sales to large U.S. corporations and 3% of federal contracts. What is slowing their progress--and do you see the situation changing?

Firestone: What's going to make a corporate purchasing agent at, say, Merrill Lynch, decide that he wants to eliminate some male supplier he's been comfortable with and make him bring in a new vendor? It's a big issue for women, because the fastest-growing woman-owned firms are those that sell their products and services business-to-business or business-to-government.

Coyne: Once you're in, you're in. It's getting that foot in the door, getting on the bid list, getting invited to conferences to bid on the work, getting a chance to get in front of the big decision-maker, once you've established credibility--those are huge hurdles.

FSB: When will women entrepreneurs finally catch up to men in terms of running $1 million-plus businesses?

Pinkwater: If a woman with a family builds a small, sustainable business, when her children get older and her priorities shift, she will look for ways to grow it in an aggressive fashion.

Coyne: We're still waiting for women to catch up in corporate America. There's no doubt, though, they now have a bigger chance of success in business ownership. In the banking world, there's no longer any discrimination that would prevent women from borrowing money to grow their businesses.

Garella: For a long time men with advanced degrees have been going out on their own and building big businesses. It's a much more recent phenomenon for women to get a higher education and to rise to upper-level management positions in corporations where they can acquire the skills to go out on their own. My sense is that given enough time and distance, the playing field will level.

O'Rourke: Years ago you would always hear, "Behind every good man there is a good woman." Well, now it's changed. Behind every good woman is a good man. When you get married, you decide which career you are going to follow, who is going to make the most money. I think we're going to see more women working and more husbands staying home, taking the kids carpooling.

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