(CNN) There are vast differences among the more than a dozen Democrats who have thrown their hats in the ring for the 2020 presidential race, but six of them have something significant in common: Should one of them win, their husband would become the first-ever first spouse.

Until now, the position of first lady has always been held by, well, a lady, and although Hillary Clinton came close, her election loss meant former President Bill Clinton didn't have a chance to see what life was like operating the other wing of the White House.

"The first dude, first mate, first gentleman," Hillary Clinton joked to late-night talk show host Jimmy Kimmel in 2016, considering the title options for her husband. "I'm just not sure about it."

True, it's a tricky subject, and first gentleman is what the husbands of female governors are called — so that could be a front-runner. And as for to whom the moniker will be applied, here are the men in contention:

John Bessler

Wife: Sen. Amy Klobuchar of Minnesota

Occupation: Lawyer and law professor

Married: 1993

Children: Abigail

Fun fact: The couple met in a pool hall.

The lowdown: Bessler is an active Senate spouse, having bonded with spouses of his wife's colleagues on Capitol Hill. He was among the first men to belong to the Senate Spouse club, an organization that meets regularly and often plans events, including an annual luncheon for the first lady of the United States. Bessler once brought a baby present to the shower for the wife of Sen. Jim Webb.

Chasten Buttigieg

Husband: Pete Buttigieg, mayor of South Bend, Indiana

Occupation: Junior high school teacher

Married: June 2018

Children: None, but Chasten Buttigieg runs the Twitter account for the couple's two dogs, Truman and Buddy, @firstdogsSB.

Fun fact: Chasten Buttigieg loves the game of Skee-Ball so much, according to Chasten Buttigieg loves the game of Skee-Ball so much, according to their New York Times wedding profile , the couple had two machines for guests to play at their wedding reception.

The lowdown: Should Pete Buttigieg win, Chasten Buttigieg would make history — twice. He would be the first male first spouse, and the first gay first spouse. At 29, he is also the youngest presidential partner of the 2020 crop, and the only millennial.

Since Buttigieg announced his candidacy, his husband has taken a leave from teaching to devote himself to being a supportive campaign partner. He travels with "Mayor Pete," as his husband is known, when he can, and promotes Buttigieg's message on the trail and via his frequent social media posts.

Chasten Glezman Buttigieg told CNN's Kate Bolduan he was excited for his husband's foray into the national political arena.

"I'm really excited for the country to get to know (Pete) on a much larger scale because he's such a breath of fresh air," he said.

He also told Bolduan that he tends to call Pete by his full name, Peter, unless he's in trouble.

"(He's) mostly Peter to me, depends on the situation we're in. Peter Paul if he hasn't done the dishes."

Douglas Emhoff

Wife: Sen. Kamala Harris of California

Occupation: Lawyer

Married: 2014

Children: Harris is stepmother to Emhoff's two children, Cole and Ella, from his previous marriage. They call Harris "Momala."

Fun fact: Emhoff met Harris when they were set up on a blind date by Harris' best friend, who made her promise not to Google Emhoff before they met in person. The couple married a year later at a courthouse ceremony officiated by Harris' sister, Maya.

The lowdown: Emhoff has been a relatively low-profile campaign spouse so far during these early weeks of the presidential campaign. Most of his law practice is back in California, although he does practice out of his firm's Washington office as well. He told Vogue magazine last year that Harris' love of cooking has helped him beef up his own gourmet chops. "She spends days thinking about the menu, grinding her own pepper, driving all over town just to find that one ingredient that we need," Emhoff told the magazine about his wife's devotion to dinners. "I've gotten pretty handy in the kitchen as her sous-chef."

Jonathan Gillibrand

Wife: Sen. Kirsten Gillibrand of New York

Occupation: Finance

Married: 2001

Children: Henry and Theo

Fun fact: Jonathan Gillibrand was born in England and met his future wife on a blind date while he was in New York getting his MBA at Columbia University. Should Gillbrand win, her husband would become the third first spouse not born in America, joining Louisa Adams (also born in England) and Melania Trump, who was born in Slovenia.

The lowdown: Jonathan Gillibrand isn't a front-and-center type of Senate spouse, nor is he often seen on the campaign trail, but he is supportive back home, taking care of the couple's two school-age sons.

Gillibrand once touted her husband's parenting style in a magazine interview, saying: "Jonathan is very focused on academics and reading. So we balance each other well in letting our children develop as young people who will hopefully be strong adults with strong character and good integrity."

Jonathan Gillbrand worked in the financial world in New York City but gave up the hustle of Wall Street when his wife wanted to move upstate and set her sights on a political career.

Bruce Mann

Wife: Sen. Elizabeth Warren of Massachusetts

Occupation: Law professor at Harvard Law School and legal historian

Married: 1980

Children: Warren has two children, Alex and Amelia, from her first marriage and three grandchildren, Octavia, Atticus and Lavinia.

Fun fact: The couple stay home and watch "Casablanca" every New Year's Eve.

The lowdown: "I'm usually introduced as Elizabeth's husband, which has been fine with me," Mann said in a recent interview, a statement that adequately illustrates the even-keeled nature of his relationship with his wife, which often includes low-key social events and anniversary gifts that don't exactly fall into the category of "typical."

In 2017, Warren gushed over Mann's grand anniversary gesture: a redone hall closet.

"Last night when I got home, Bruce met me with a sweeping 'ta-da!' and flung open the door to the hall closet. New shelf. Hooks. A place for grocery bags. 'Happy Early Anniversary!' " Warren wrote in a Facebook post. "Ok, that may not seem very romantic, but I LOVE organized closets. (Yes, I hang all my jackets together, arranged by color.) But I have zero time to hang a shelf and even less time to get out the drill and put up some hooks. The new shelf and hooks (and Bruce's enthusiasm for them) made me laugh — and reminded me just how sweet and thoughtful Bruce always is."

Warren also says it was she who proposed to Mann, switching up the conventional roles. Mann has admitted he never anticipated their lives would be so much in the spotlight, but he's gotten used to supporting his wife and intends to be a presence as the campaign heats up.

Abraham Williams

Wife: Rep. Tulsi Gabbard of Hawaii

Occupation: Filmmaker, cinematographer

Married: 2015

Children: None

Fun fact: Williams, like Gabbard, is an avid surfer, Williams, like Gabbard, is an avid surfer, so when he decided to propose , he made a special flotation device covered in gold duct tape for the ring and attached it to his surfboard. As the two waited to catch the perfect wave, Williams asked Gabbard if she would marry him.

The lowdown: Rarely photographed, Williams is clearly more comfortable behind the camera than in front of it, which is just fine by his wife, since he is now putting his filmmaking skills to use documenting her campaign.

That's actually how the two met, several years ago in Hawaii, when Williams volunteered to shoot Gabbard's campaign ads. They were friends first, but eventually kindled a romance at a friend's party, quickly realizing they both loved the outdoors.

Williams is perhaps the least-seen among the candidate spouses, and he has yet to weigh in on any of his wife's political philosophies, but Gabbard is thankful her husband is at least with her when he can be on the campaign trail.

In February, to mark Williams' 30th birthday, Gabbard posted on Facebook from Iowa: "Happy birthday to my amazing husband, Abraham! It was yesterday and we spent it on the road ... Iowa city to Grinnell to Council Bluffs to Des Moines! Thanks to Molly's Cupcakes in Des Moines for helping us celebrate with amazing vegan cupcakes (for breakfast)."