A decade ago, Colorado entrepreneur and philanthropist Jared Polis made history as the first openly gay man elected as a nonincumbent to Congress. But most voters did not get a glimpse of his longtime partner Marlon Reis until the night Polis won the Democratic primary, when the couple created a sensation by sharing a hug onstage at a victory party.

“It was kind of zero to 60,” Reis recalls. He had initially been reluctant to be visible in the campaign because “we didn’t know if it would somehow negatively affect Jared’s chances of getting elected.”

This year, Polis is running for governor, and the family he has created with Reis is very much a part of the effort. Their six-year-old son, Caspian, narrates a campaign ad on Polis’s plans for universal pre-kindergarten. A Facebook video shows the couple huddled on a bunk bed with Caspian and their scene-stealing three-year-old daughter, Cora, reading an iPad storybook — which happens to be A Day in the Life of Marlon Bundo, Last Week Tonight with John Oliver’s bestselling parody of one about Vice-President Mike Pence’s pet. In Oliver’s version, the rabbit falls in love with another boy bunny.

The Polis family’s increasing comfort in the spotlight, and their realisation that it can be used to illuminate things that are important to voters, is a healthy development in politics.

While not as remarked upon as the flood of women running for office, the 2018 election season has seen a surge in candidates who publicly identify as lesbian, gay, bisexual or transgender. The LGBTQ Victory Fund, an advocacy group, says it counts nearly 400 vying for offices from school board to governor.

For straight candidates, it is expected — practically demanded — that they write spouses and children into the narrative of their lives and testaments of their values. The image of a hummingly functional home life can go a long way towards humanising even the stiffest of politicians.

But for LGBTQ people entering the rough environment of politics, the choice of what, if anything, to tell voters about the people most central to their lives is more fraught than for straight couples. That remains true even in an era where gay marriage is legal across the country and supported by nearly two-thirds of Americans.

In their openness, Polis and a handful of others, such as Democratic gubernatorial contender Richard Madaleno in Maryland, remain the exception.

There are many others who are like Gina Ortiz Jones, a former Air Force intelligence officer who last week won a runoff in Texas to become the Democratic nominee in one of the most closely fought congressional districts in the country. On Facebook, she has described the anguish and isolation she felt serving in the military at a time when “Don’t Ask Don’t Tell” was the policy.

She still struggles with how much of herself to keep private, understandably so.

“My girlfriend teases me sometimes for not sharing enough about myself on social media, particularly as I endeavour into an arena where people need to know the person, before they want to hear the policies,” Jones wrote in October, referring to a partner she did not name.

“I can’t help but think that some of that is still related to the precautionary steps I took as a cadet and officer. All this to say, there are effects to not coming out, or feeling as though you’re not able to come out.”

LGBTQ Victory Fund president Annise Parker, who broke barriers herself as mayor of Houston, says candidates have different reasons for their continued reluctance to expose their significant others and children to all the ugliness that comes with a campaign. There is still the potential for backlash, of course, and Parker said that some partners remain in the closet. What’s more, most candidates do not want their sexual orientation to overshadow their positions on issues that matter most to the voters whose support they are seeking.

In her own case, Parker said, her children and the woman who is now her wife “had zero interest in being front and centre in a campaign”.

For now, gay candidates and their loved ones also have to get used to a certain amount of inquisitiveness that straight politicians do not experience.

“People have a lot more questions,” Reis says. “With our family, there’s a curiosity about how we even have a family.”

History is being made this election year in many ways — and one of them is showing how far we’ve come towards understanding that families can look different, but that they all start with love.

• Karen Tumulty is a Washington Post columnist covering national politics. She joined the Post in 2010 from Time magazine and has also worked at the Los Angeles Times