Jen Crane and Tom Frohlich are banking on the generosity of friends and family to collect as much money as possible when they get married — but not for selfish reasons.

In fact, the couple is quite embarrassed at the thought of receiving a bounty of traditional wedding gifts, be they large checks or fancy dishes. That is why they are instead encouraging guests to make donations in their honor to three charities: the Sierra Club, Girls on the Run and Youth in Focus.

Crane and Frohlich, who will exchange vows next month before 80 guests on Orcas Island off the north coast of Washington, are part of a tiny but growing group of couples turning their weddings into philanthropic opportunities. It is a trend that is picking up momentum, industry officials said, with help from a handful of Web-based nonprofits that serve as virtual intermediaries between couples, charities and guests.

While these decisions are largely a reflection of couples' altruism and other personal values — Crane, for example, volunteers with the Sierra Club — many who are setting up charitable wedding registries acknowledge more practical motivations. For instance, as the average age of U.S. newlyweds rises and more couples live together before tying the knot, there is not as much need for cookware and other traditional gifts as in previous generations.

"We're in our 30s, so it's not like we need a lot of stuff," said Crane, whose charitable wedding registry is managed by the I Do Foundation, a Washington, D.C.-based nonprofit that sends e-mails to guests informing them of the couple's unorthodox request.

Of course, there are some things, like a new camping stove, that the couple would be happy to receive. And they know that certain guests, particularly older family members, will insist on buying a gift that can be wrapped and tied with a bow. For these reasons, Crane and Frohlich also set up a more traditional gift registry through the same foundation, though it requires participating retailers, such as REI and Linens 'n Things, to give a small percentage of their sales to the charities the couple selected.

"We were looking for ways to cut back on the excess," explained Crane, who like many brides-to-be these days was astounded by how quickly the costs of a wedding can escalate. "The whole wedding industry is a little bit out of control."

Because weddings are increasingly secular "commercialized" events — Americans spend $26,000, on average — "people are looking for a way to reflect that they are deeper than all that," said Carley Roney, co-founder of the wedding information portal The Knot Inc.

Some couples are making donations in honor of their guests instead of handing out party favors, while others are donating leftover food to nearby homeless shelters. "The wedding was originally a broader community celebration. You fed your entire village," Roney said.

But with more than 2 million couples married in the U.S. last year and perhaps just a few thousand setting up any variety of charitable gift registries, Roney said the trend is hardly putting a dent in the profitability of the wedding industry.

Couples who have incorporated charitable giving into their events said it helped to keep their priorities in check.

Georgia and James Markarian of Los Altos, Calif., felt particularly uneasy last year while planning the details of their wedding so soon after the massive South Asian tsunami that killed more than 200,000 people across 12 nations.

"We were looking at people who had no homes — and spending $500 on sorbet," the 33-year-old Georgia Markarian said, recounting her decision to find some way to use the couple's Napa Valley wedding as an occasion to help others.

The Markarians set up an online charitable wedding registry through JustGive.org, a nonprofit that has collected some $850,000 and directed it to various charities on behalf of newlyweds since 2003.

The Markarian wedding alone netted $5,000 for The Red Cross, Habitat for Humanity, Save the Children and United Way — all of which were involved in the international relief effort following the tsunami that inspired the Markarians to contact JustGive.org.