(ABC NEWS) -- When Kathryn Hamm's mother looked for a shower gift for her daughter's gay "wedding" ceremony, all she could find were photo albums with images of traditional male grooms and female brides.
And Hamm herself had embarrassing moments when she and her bride-to-be registered for gifts and one had to be the "groom."
"One sales person presumed that I was the bride and Amy was my maiden of honor or sister or something," said Hamm, now 43, who is not legally married, but lives with her partner and her 6-year-old son in northern Virginia. "It was a ridiculously awkward moment … horribly uncomfortable for all of us."
And once the day arrived, the photos were a "mixed bag," she said.
For Valentine's Day, check out "Capturing Love," romantic lesbian and gay wedding photography.
But Hamm's heartbreak in looking for sensitive vendors for her lesbian wedding became her mother's obsession to support her daughter.
"I was thrilled they were getting married, but my only standards were a straight wedding," said Gretchen Hamm, now 67 and a human rights advocate in Dallas.
Co-author Kathryn Hamm and the mother who inspired her, Gretchen Hamm.
"I wanted to take them this book where you record the wedding, so I go down to Cedar Springs, our gay area, expecting to find exactly what I needed. You think everything has been invented. But there was nothing."
Kathryn Hamm describes her mother as a "Texas steel magnolia," a reference to the 1989 movie about a feisty circle of girlfriends. "She is a force of nature."
Realizing gay couples were underserved, Gretchen Hamm started her own online wedding boutique, now called GayWeddings.com, and in 2004, her daughter, then a teacher, got into the business as well, growing it to 52,000 vendors.
"She was way ahead of her time," said Kathryn Hamm, "Most people looked at her like she was crazy. … It grew out of her passion for me."
Today, same-sex marriage is legal in nine states and the District of Columbia. And while more wedding products are available to this niche market, it's still hard to find a photographer with the sensibility to capture gay love in a way that feels natural.
So Hamm, now president of their mother-daughter company, has collaborated with Thea Dodds, an award-winning New Hampshire photographer and founder of Authentic Eye, to publish a groundbreaking guide to getting the same-sex engagement and ceremony right: "Capturing Love: The Art of Gay & Lesbian Wedding Photography."
A softcover version is available through Lulu.com. It features stunning photos from 38 top gay and lesbian wedding photographers. On Valentine's Day, they will release an e-version on Kindle through Amazon.
"Weddings are changing, and photography education needs to change, too," said Hamm.
When both grooms are dressed in black tuxedos, how do you make sure the image doesn't become a blur of black with two heads? Can you ask a lesbian newlywed to "dip" her bride? The rules are often upended. What works for a man and a woman often doesn't always for a same-sex couple.
"If you try to apply everything you are taught about wedding photography and how to pose a man and a woman -- with a same-sex couple, it just doesn't fit," said Dodds, 35, who has shot more than 200 weddings. "It really is mechanical."
"You learn techniques," she said. "With two men it can be as simple as having one take his coat off."
Inexperienced photographers sometimes produce images that suggest the couples are "siblings, not lovers," said Dodds, missing the romantic connection. Having a conversation beforehand about gender identity can help, she said.
"Looking through thousands of wedding images to make a selection for the book, a lot of times two men started to look like executive portraits to me," said Dodds. "There is no intimacy or emotion, no commentary on their relationship."
One of their favorite photos in the book was taken when a male couple kissed. But the image is shot only of their feet -- one on tiptoes, the other flat on the ground.
"It has a message of intimacy outside the frame," said Dodds.
"A common mistake" in photographing lesbian couples happens when "one wears the pants and one wears a gown," according to Hamm. "We basically pop them into male and female roles. It's very complex, but there are aspects of gender expression that transcend sexual orientation. The bottom line is to understand how the couple is comfortable being themselves."
Guessing the power dynamics and staging a pose, such as asking the bride in pants to classically "dip" her partner in a dress, or suggesting one groom embrace the other without an understanding of how they relate to each other, can be "at best, awkward, at worst, offensive," she said.
At Hamm's wedding on Maryland's Eastern Shore during Hurricane Dennis, both brides wore champagne and ivory dresses with sandals, their toenails painted blue.
She and her partner had little guidance because few same-sex couples had even contemplated the institution of marriage 14 years ago.
"Legal recognition was not part of the conversation -- it was a smaller, more private ceremony situation," said Hamm. "For most folks, it had not occurred to them to do this then. But those who did, wrestled with what does it look like and why does it matter?"
As for the cultural shift that has happened since the couple first met, Kathryn Hamm said, "It's astonishing how much things have changed. More products are in neutral language. Instead of a bride and groom, the symbols are diverse -- two glasses or two doves. There is a much broader range of tasteful stationery lines. Couples can find more cake tops with themselves in it -- two grooms and two brides and mixed-race couples."
"What is important is to see ourselves reflected and embraced," she said.
Gretchen Hamm, whose loving attitude jump-started Hamm's career, said she never hesitated when her daughter wanted to make a lifelong commitment to another woman.
"We are a very close-knit family," she said. "We love Kathryn no matter what, but our script looked different. All of a sudden we had two daughters-in-law and son and a daughter. Nonetheless, we loved her and embraced her."
Gretchen Hamm hosted a wedding reception for the couple in Dallas among friends for whom the concept of gay marriage was "totally new."
"They were so open-minded and I realized that it is a lack of education and not about prejudice for the most part," she said.
Kathryn's father was more hesitant, but when his daughter wanted to formalize her commitment in a ceremony, he quickly changed.
"It was the language of a wedding that he understood. It meant that we had crossed a threshold," said Kathryn Hamm. He even sang in the wedding.
Both grandmothers also attended, even though they did not fully agree with the idea of same-sex marriage.
But, said Hamm, "It's undeniable when you are in a room with two people who promise themselves to love and commit -- all the things my family is about. You can't help but support them."
Click here for more about this story from ABC News.