"Nothing has changed! We fight, discuss, we are the same, we are like yin and yang," says an outspoken Stefano Gabbana, of having reached the 30-year mark in his partnership with Domenico Dolce, looking over at his business partner and best friend with a grin.

"Now, we are just a little bit more old," chips in Dolce, "Now, we're old bastards!"

They burst into laughter.

Since breaking into fashion in 1985, with less than US$2,000 to their name, Dolce and Gabbana, who used to have a personal partnership as well as a professional one, have become two of the business' most renowned names while having managed to keep an independent company on an even keel in a turbulent industry.

"I think it's a very complicated moment in fashion," says Dolce, who, today, is very talkative. "Things are changing a lot. I don't know what is the future [of fashion]. We are not a very fresh label, we are not avant garde, but [as a designer] if you try to find a personality, have a memory and have a style, and work around this, this is forever."

The duo, tanned and relaxed, are ensconced in a suite at the Four Seasons Hotel Hong Kong. They are surrounded by an entourage and, outside, there is a noticeable security presence (after all, it has been but a few days since they made a number of high-profile enemies - including Elton John and Madonna - by disparaging as "synthetic" babies born through in vitro fertilisation and calling them "sperm selected from a catalogue", in an interview with an Italian magazine. But more on that later).

The pair have recently been to Thailand, where they paid a call on several ethnic minorities, including the Karen "long neck" tribe.

" Bellissima!" gushes Dolce, "We found some girls, so elegant, beautiful … I see the most beautiful baby in my life there!"

The trip has clearly made an impact; by the end of our interview, the designers will have asked me about books on ethnic tribes in China and folk culture. And one of their staff will have been sent on a mission to the closest Page One bookshop.

"Travel," says Gabbana, "it really helps to clear and clean your mind and your brain. When you are around different cultures, the colours, the attitude, the elegance, maybe inspire you."

Their next stop is Shanghai, for the launch of their first photo book with an Asian athlete: two-time Olympic badminton champion Lin Dan, who was shot by Dolce and supermodel friend Naomi Campbell.

The coffee table book is the latest in a line dedicated to male beauty: footballer Lionel Messi and the complete AC Milan and Chelsea teams have featured in previous tomes. The physique, style and prowess of male athletes are presented in moody photos, some of which could be considered risqué, featuring buff bodies in various states of undress.

"He was very good looking and fashionable," says Gabbana of Lin, who the designers first met at a dinner in Beijing three years ago. "He doesn't speak Italian or English but, with a translator, he said, 'I'd love to work with you.'"

Adds Dolce, "When he saw the book [we did] with Lionel Messi, he went crazy. He said, 'I want to do the same as this.'

"Firstly, he is a very beautiful guy, very stylish, not just like a model. People like him, who have a [strong] personality, have a lot of character. When someone has a point of view, they are always easier to shoot."

At first, the designers picked Lin's outfits but, by the end of the shoot, the athlete was happily styling himself. And so, "the result is the point of view of Dolce and Gabbana together with the point of view of Lin Dan", says Dolce.

"In my opinion, in all Asian areas, this is a good moment for fashion," he continues. "The magazines are more beautiful, they have more courage. The Chinese people who are fashionable are [also] very good looking; and it doesn't look cheap."

Since Asia, and China in particular, is a key market for the brand, this project makes sense. A local edge in a crowded market may well capture the loyalty of consumers who are no longer falling over themselves for expensive labels just because they hail from the West.

Their playful, sensual Italian aesthetic is gaining ground in Asia's less developed countries, too, where Dolce & Gabbana's feminine 1950s silhouettes, vibrant colours and prints still hold significant cultural cache among the bold and beautiful society set. One client who buys Dolce & Gabbana for her multibrand fashion store in Vietnam, for example, devours the brand's signature animal print every season.

"They love it there," says Gabbana. "She says, 'You need to come to Vietnam and see all the most beautiful ladies, aristocratic and rich, going around the city on bicycles wearing your clothes!"

It is an invitation they have yet to accept.

With an ever-growing horde of social media-savvy designers biting at old establishment heels, Dolce admits it's not easy to stay fresh, exciting and relevant every season, or "do something new about the Dolce & Gabbana DNA".

Having no shareholders, though, means they can swiftly shift their business model to suit their own narrative. For instance, in 2011, they foreshadowed high fashion's move to refocus on the luxury sector by shutting down what appeared to be a profitable offshoot, the diffusion label D&G (although the official line is that it has been folded into the main collection). Following suit, Marc by Marc Jacobs shut down its diffusion line this year and Jean Paul Gaultier closed his ready-to-wear line last year to focus entirely on couture.

"Yes, we suffered in the beginning [because of that move] … and lost a lot of money," says Dolce.

"But now, we are [making] more than before," says Gabbana, completing his partner's sentence. "We think that it's much better to concentrate on luxury."

The luxury he's talking about includes the one-of-a-kind couture lines the brand began putting out three years ago. In a drastic move, late in their careers, the pair launched Alta Moda (the women's couture line) and Alta Gioielleria (the jewellery line) in 2012, and this year unveiled Alta Sartoria (the men's line). The labels, within reach of only the super rich, have helped breathe new life into the brand.

Inspiration came from the old days of haute couture. Dolce and Gabbana read up on Cristobal Balenciaga and Christian Dior's couture salons of the 50s, when "shows" would last up to five hours, with breaks for tea, lunch and cocktails.

It's not the 50s now, of course, but the designers would prefer to keep the Alta lines out of the social-media glare.

"We are not interested in bloggers now," says Gabbana. "We started working with them in the beginning, a long time ago, but afterwards we said no; not to the people, but more to a system that may confuse the market."

"First of all, we are not a young label, we are in the market for a long time," adds Dolce. "We started with being very 'fashion', cool, trendy and now we want and dream about the essence of Dolce & Gabbana - like a family, the mother, father and baby: the elements of what is in the Dolce & Gabbana DNA."

And it is the traditional family that has inspired the duo's latest ready-to-wear collections: 30s- and 40s-style men's suits and sophisticated vintage silhouettes for women, although that's not a million miles away from what we've come to expect from the duo.

The runway shows (each with a spectacular finale) have become increasingly complicated, dramatic and important in forging a sense of the new, albeit with a recognisable brand identity.

The autumn-winter 2015 women's line, which was debuted in February, is an ode to motherhood. A heavily pregnant Bianca Balti walked the runway and other models carried babies on their hips and led little girls by the hand. Form-fitting black lace dresses made an appearance, of course, but it was the floral (mostly rose) embroidered numbers in satin hues of pink and pale blue that celebrated the specific femininity. Scribbles from Dolce's nephews and nieces were used as motifs on chic shifts, A-line dresses and coats. "I love you" in Italian, English and French was embroidered onto clothes and a classic "Madonna and child" painting was printed large on a black lace dress adorned with roses.

The January launch of the men's collection was a veritable feast of family-centric motifs - and titled La Famiglia. It included sepia-toned family photos - alas, not the designers' own - printed on graphic T-shirts and baroque jackets and jumpers embroidered with ornate gold family crests. Men of all ages, from the silver-haired to those barely out of their teens, were cast. The final scene was set up like a huge family portrait, with models being joined by mothers, fathers, grandmothers, grandfathers and tots on knees.

"When we [thought] about this show, we started with the idea of the man with a family - and we want to continue from this because this love, whether you are an Italian, Chinese or Jamaican, it's a universal love."

It was perhaps ironic, then, that it was their thoughts on family that landed them in so much hot water. In March, when they declared "the only family is a traditional one" in an interview with Panorama magazine, it set off a PR firestorm of unforeseen proportions.

"The family is not a fad," Gabbana had said to the Italian publication, when discussing their inspirations. "There is a supernatural sense of belonging."

Dolce championed the traditional family set-up while criticising IVF.

Elton John soon took to Instagram to condemn the designers, calling them "judgmental" and "irrelevant", creating the hashtag #BoycottDolceGabbana.

Gabbana hit back by calling the British singer "ignorant".

Unfortunately for John, only days later he was photographed by the press carrying a Dolce & Gabbana shopping bag - which resulted in a headline that Gabbana gleefully posted on Instagram.

The controversy went viral: Victoria Beckham supported the boycott while other celebrities wondered why it mattered that a fashion designer was personally against IVF.

Dolce and Gabbana then claimed their comments had been taken out of context and released "clarifying" statements: "I grew up in a traditional family," said Dolce. "There are other types of families and they are as legitimate as my own … I was talking about my personal view, without judging other people's choices and decisions."

"We firmly believe in democracy and the fundamental principle of freedom of expression that upholds it," posted Gabbana. "We talked about our way of seeing reality, but it was never our intention to judge other people's choices."

The controversy will, of course, pass, but it seems to have saddened the designers, who like to be seen as champions of a warmer, more human approach to fashion. From street casting "normal" people in Sicily to walk on their runways, to favouring actresses and models who do not conform to the prevailing industry biases, Dolce & Gabbana's reputation had not been one of exclusion.

"We are open people," says Gabbana, "all the people know this if they watch our shows."

As our interview draws to close, I defy PR instructions and broach the subject head on. There is an awkward silence before they both say, "No comment."

But Gabbana cannot resist.

"We feel that we don't say anything wrong - for us it's just a personal opinion. We are gay, we love gay couples and gay adoption. It was just a personal opinion.

"Maybe we used a wrong word but we are totally open-minded."

So, there you have it, Elton. Keep your hair on; it was just a misunderstanding.