TORONTO -- It's been 50 years since the debut of "Guess Who's Coming To Dinner" yet film portrayals of interracial couples remain a rarity in Hollywood.

The 1967 movie was a watershed in its positive depiction of the relationship between an accomplished black doctor (Sidney Poitier) and his white fiancee (Katharine Houghton), at a time when interracial marriages were still illegal in many U.S. states.

A half-century on, there are few examples in modern films of romances involving interracial couples. If anything, the subject of race tends to be the focal point of such pairings -- such as Spike Lee's 1991 film "Jungle Fever" and 2006 romantic comedy "Something New" -- or are based on real-life stories like the Golden Globe-nominated "Loving" and "Lion," and forthcoming biopic "A United Kingdom."

"Loving" writer-director Jeff Nichols says Hollywood seems reluctant to give screen-time to interracial couples unless "you're trying to make a point about something."

"Where we need to get is that you could have (interracial couples) included and it not be something you're trying to make a point of -- it just happens. This just is," said Nichols during an interview at the Toronto International Film Festival.

"I'd like to think we're getting there. I think it will happen. But I also think writers work from their own experiences, and the more diversity that we get in these groups of storytellers and these writers, I think the better the reflections will be."

"Loving" centres on Mildred and Richard Loving, the Virginia couple at the heart of a historic 1967 U.S. Supreme Court ruling that unanimously struck down all anti-miscegenation laws. Still, it wasn't until the year 2000 that Alabama became the last state to overturn laws that criminalized interracial relationships.

"We're talking about hundreds of years of institutionalized racism in the form of laws, but also in the form of society, hearts and minds," said Ken Tanabe, founder and president of Loving Day, a global network of annual celebrations commemorating the landmark Loving case.

"Bringing that to the present day, you don't reverse something like that overnight when it's so deeply ingrained. So I think the absence of interracial couples and families and multiracial individuals in film and television is a part of that system," added the New York-based Tanabe, who is of Japanese and Belgian heritage.

Tanabe recalled a 2013 Cheerios commercial featuring a black father, white mother and biracial child. The backlash to the ad produced enough vitriol on YouTube that the company requested that comments be turned off.

General Mills, which owns Cheerios, had said it was looking to reflect the changing U.S. population with the ad, and didn't relent in the face of negativity. The same fictional family was brought back for a 2014 SuperBowl commercial.

"Those who depict interracial couples and families in a non-controversial way are trying to reset the standard to demonstrate a way forward," said Tanabe.

Mixed unions made up about 4.6 per cent of all married and common-law couples in Canada in 2011, according to data from the National Household Survey, up from 3.9 per cent in the 2006 census, and 3.1 per cent in 2001.

Vancouver-based filmmaker Jeff Chiba Stearns explored his own heritage in the documentary "One Big Hapa Family," and set out to discover why everyone in his Japanese-Canadian family married interracially after his grandparents' generation.

His latest documentary "Mixed Match," which looks at the need to find mixed ethnicity bone marrow and cord blood donors for multiethnic patients, won awards at the Vancouver Asian Film Festival and Toronto Reel Asian International Film Festival.

"It's great that these festivals exist because there's a platform for people that want to tell these diverse stories, but again, it's still kind of within the independent realm," said Chiba Stearns.

"It's like guys like me who are (saying): 'Yeah, I'm mixed, so I'm going to tell the mixed-race experience.' If I was doing Hollywood stuff, I would definitely be putting that in.

"The only way that we can be represented properly is by actually speaking from our own experiences. I think it is hard for some Hollywood executives who maybe are not well-versed in those areas to really think about it," he added. "Maybe there's some of that happening, but it's also the writers, the directors, the producers.

"As long as we have the creatives who identify as mixed or particular minority groups, we will get some of those stories or characters seeping into our movies. It's just one of those things that we've got to fight the good fight and make movies that reflect our society -- and that's what's happening."

- With files from The Associated Press