Christmas is meant to bring people together, but come December 25, you might find yourself sitting across the table from someone with a very different outlook on life.

You might think they're too politically correct; they might think your jokes are kinda sexist. You might think their generation has left a mess; they might think young people are entitled and avocado toast is what's keeping you out of the housing market.

So what happens if someone says something that you find offensive? Do you call them out on it or try to keep the peace?

Before you do anything, follow these expert tips.

1) Make sure you're actually offended and not just policing people's behaviour

Lauren Rosewarne, a senior lecturer at the University of Melbourne, told us she's conflicted about this issue as she's someone who generally avoids confrontation.

"Equally, I've grown very exhausted by the call-out culture whereby everyone feels it's OK to police the words and behaviour of others in an often-aggressive way — after having appointed themselves arbiter of all that is good," she said.

However, she said there are times when it's necessary to speak up.

"If you're genuinely offended — and not just third-party offence-by-proxy — then I think the best way I'd suggest to handle it is framing it along the lines of, 'I'm upset when you say things like that'."

She says doing this makes it about what the comments do to you on a personal level, and stops it from just being you on a high horse.

Matthew Beard, a fellow at the Ethics Centre, said you should also ask yourself if the comments were actually offensive or just annoying.

"There's a difference between something that grates on our nerves and something that contradicts our values and principles — or those of the community," he said.

2) Take a moment to consider whether the comments were actually intended to be offensive

If they weren't, Dr Beard said it might be better to simply explain and educate — "maybe when they're slightly more sober".

But if the comments are obnoxious or mean-spirited, that changes things, especially if they directly affect someone else at the table.

"For instance, if homophobic comments are being made in the presence of a gay family member, there's a more compelling reason to speak up," Dr Beard said.

He said it might be easier for you to speak up as a bystander than for them to defend themselves.

3) Keep in mind that you're unlikely to change your racist uncle's view

So your efforts to correct him might not be appreciated.

"Holding the Christmas dinner table hostage to your position is likely to be just as unpleasant for everyone at the table as having to hear yet another racist tangent from Uncle Bill. Even if you are the one in the right," Dr Rosewarne said.

But Dr Beard said it might still be worth speaking up.

"You might not be able to change someone's mind, but you might be able to change the subject, get them to shut up, or simply show them that their comments aren't shared by everyone at the table. That's still a difference," he said.

"The question then becomes whether speaking out is the best way to achieve that goal, or whether a bit of social nous and imagination could get the same result in a less combative way."

For Dr Beard, it's a balancing act — he points to former Army chief David Morrison's famous principle "the standard you walk past is the standard you accept", but also notes "you can't fight a war on every front".

"If we were able to maintain the relationship, we might be able to help the other person change gradually — from a position of care and compassion — as well as keep the peace and preserve the connection," he said.

4) You probably already know what is and isn't OK to say around your family

Dr Rosewarne said you shouldn't pretend you're a babe in the woods.

"For some families, sex and politics and religion will never have a comfortable place at the table; for others, there'll be no meals without an enthusiastic stoush," she said.

"This isn't likely to be your first rodeo: you already know your family and what's tolerable to them."

She says you should do your best to stay clear of sensitive topics and come prepared with some neutral topics (family, work, weather) that can help steer things back on track.

5) A bit of good old-fashioned empathy can help

You don't have to agree with someone to understand why they think the way they do.

"It's easy to dismiss our relos as bigots, zealots, liberals, conservatives or whatever without getting into their shoes and really understanding how they see the world. That's especially true when there are generation gaps," Dr Beard said.

So consider the best reasons your millennial daughter or baby boomer granddad might have for thinking the way they do.

"We might then assume people haven't heard another point of view, or have good reasons of their own, rather than thinking they're bigoted or idiots," Dr Beard said.

But he says you might also ask what value the relationship has if you can't challenge each other on "stuff that really matters".

"If you really care about someone, would you allow them to keep being racist, sexist or whatever without doing your best to change their views?" he said.

6) If there isn't respect in the relationship, think about parting ways

According to Dr Beard, we're under no obligation to sacrifice our own wellbeing on "the altar of family harmony or politeness".

"If someone is insulting you or making you feel small, you don't have to keep trying to change their mind, engaging in debate or even spending time around them at all," he said.

He said while people feel strong obligations to their family, it's about give and take with "each person respecting the other and giving them what they deserve".

"If that's not happening, you're not really in a genuine relationship at all," he said.

Dr Beard said parting ways might be better than "sticking around until we're bitter, contemptuous and hateful" towards them.