The Web site for next month's Gay Life & Wedding Expo in Washington had barely gone up last fall, event organizer William Harrison recalls, when the phone started ringing.

Icelandair was first. Michael Pierorazio, operations manager at the airline's Columbia-based U.S. headquarters, had put together a sponsorship offer that included a free honeymoon trip to Denmark to be given away at the event.

A gaggle of Washington-area Marriott and Renaissance hotels followed - including downtown's tony Mayflower - along with the gift registries at Bloomingdale's and Kitchen Etc. Eight financial planners from American Express wanted to sign on, Harrison said, but company policy allows only one per trade show, so they were fighting it out among themselves.

While the national debate over gay marriage rages, pitting calls for a constitutional ban against same-sex couples tying the knot in cities around the country, the wedding industry is taking a more practical stand - and cashing in.

Gay weddings have become a booming niche market, and businesses, from big hotels to local caterers to wedding photographers, are avidly wooing the happy couples.

The recent flood of same-sex weddings in San Francisco, with Massachusetts possibly soon to follow, has upped the ante. Events like the Washington expo (www.dcgayexpo.com), scheduled for April 4 at the Galleria at Lafayette Center in downtown Washington, are being held in Boston, New York, Las Vegas, San Francisco and San Diego.

Online, couples can find links to gay-friendly wedding professionals at sites including RainbowWeddingNetwork.com and www.AltWed.com. They can also use software such as My Gay Wedding Companion to plan their own.

The momentum seems almost self-perpetuating, Harrison said. The more same-sex couples have weddings, the more realize they can. "We're helping to take our community to the next level," he said. "[Marriage] doesn't belong to 'them' anymore. It's all of ours."

Demographics

The politics of the moment aside, the gay wedding boomlet is being driven primarily by demographics. Robert Witeck, president of gay marketing consultants Witeck-Combs Communications in Washington, estimates the size of the nation's lesbian and gay market at between 14 million and 16 million people, with a projected buying power of $485 billion.

Witeck, who has helped major corporations including American Airlines and Ford Motors market to gays, said the wedding industry should have no trouble appealing to same-sex couples. "It's about capitalistic acts between consenting adults," he said.

According to the Conde Nast Bridal Infobank, Americans marry at the rate of about 2.3 million couples per year, spending more than $50 billion. Conde Nast pegs the cost of the average wedding at about $22,000, honeymoon not included.

The average for gay weddings is slightly lower, about $15,000, said Cindy Sproul, co-owner of RainbowWeddingNetwork.com in Asheville, N.C. Almost 4,000 wedding professionals across the country advertise on the site, 90 percent of them straight, she said.

William Harrison was motivated by a similar urge to bridge the gap between wedding professionals and same-sex couples. He and his partner of three years (who asked not to be identified because he is in the military) figured that a gay wedding trade show would be a natural.

The couple, who publish a local tourist guide, DC Navigator, and a bridal magazine, Bride's Day Maryland, thought they had the contacts in the gay community and the wedding industry to do it right.

"We were really concerned about someone trying to do it first and maybe not doing a good job," Harrison said. "If you do something like this and it ends up tanking, that could set a really bad precedent."

Since announcing the expo, they've lost one Bride's Day advertiser, Harrison said, but overall response has been positive. They're expecting more than 70 vendors at the event, along with lesbian and gay couples from Delaware and Pennsylvania. And they're thinking about the Washington Convention Center for next year's event.

Dollars and cents

Nancie Cameron, whose Silver Spring company, Creative Cakes, will be at the expo, said that for her business, about the only difference between gay and straight weddings is the cake decorations. Lesbians usually like rainbow colors, and gay men take a more "tailored" approach, she said.