Why Saengtip feels a sense of dread when she's in airports with her 18-month-old son.

Every mother knows all the preparation that goes into travelling with their families. And these days, with an ever-changing world political climate, searching Google for “what do I need when travelling with kids” is a necessity before each trip.

This is what Mamamia campaign strategist Saegntip Kirk found herself doing before a recent holiday to Bali with her partner, Tony, and 22-month-old, Hugo.

Kirk discovered the standard information about liquids and baggage allowances, but one piece of information made her heart skip a beat.

“Another mum in a chat forum warned that if you’re travelling with a different surname to your kids, you need to be very careful, and really prepared that security will ask you how you’re related,” she said.

“Hugo’s dad and I aren’t married, and Hugo has his dad’s surname as his last name, and my surname as his middle name. But I realised that wouldn’t be enough. I thought, there’s a chance that airport security wouldn’t believe I was his mum.”

It was a terrifying thought, and it raises a complicated issue. These days, more than ever, with families not following the traditional surname process of a man and a woman marrying and having one family name, not everyone within a family unit will share the same last name.

Married, divorced, de facto, not married, re-married, maiden names being kept, travel with extended family such as grandparents or aunts and uncles, travel with kids that belong to other parents: factor all of those scenarios in, and you can imagine it’s a minefield for airport security.

And for the safety of all of our children, it’s one that’s vitally important they get right.

As Kirk said, “authorities need to evolve and accept that families won’t always share the same last name.”

Until that happens, though, it remains a common issue throughout the world. The Guardian reported in 2014 that an estimated 600,000 women had been questioned about their relationship to a child they were travelling with in the previous five years, causing panic, embarrassment and even missed flights.

Saengtip’s experience with Hugo.

Kirk explained to Mamamia that she knew from a young age that surnames are what society sees as the way families are grouped together.

“Even when my mum re-married, and changed her surname, I wanted mine changed, too, so we would be seen as a family.”

Wanting to avoid having to explain the parent-child relationship constantly was one of the reasons why Kirk insisted that her maiden name be included in Hugo’s name. But to her dismay, she’s still found herself having to sign emails, and say in phone calls,” Saengtip Kirk – Hugo’s mum.”

“It gets a little frustrating when your obvious relationship to a child – by the fact you’re emailing or calling – still needs to be justified, just because you have different surnames.”

Kirk also said that the presumption of having the same surname as her partner, and that they’re married when they’re not, is also irritating.

“I always get called Mrs Vorasarn! It drives me nuts! Can’t people just accept that you’re not married, or that you didn’t change your surname if you are?”

“Why is the surname still the number one way to define a family?”

In readiness for a potential airport interrogation, she ensured she had not only Hugo’s passport, but also his birth certificate, that named her specifically as his mum.

Luckily, Hugo's passport and their relationship was accepted at all points during their travels. But as Kirk said, the situation made her realise that it was the the first of many formal explanations she would have to do.

"The more things Hugo does, the more I will have explain myself and prove that I'm his mother, and that's just sad, because it's only based on surname. We should be more accepting of different families by now.

"Marriage and changing your surname can't be the only way to make us a 'legitimate' family and prove our relationship."

What else can you do to prepare?

Australian lawyer Hannah McKinnon, accredited family law specialist told Mamamia last year that the strict standards at border security would not go away soon, because they are related to increased terrorism controls.

“As we see the whole world’s borders clamp down, these issues that weren’t an issue 10 years ago are obviously starting to be more common,” she said.

McKinnon also warned that parents that have children with a different surname should take a portfolio of documents with them - including a passport and birth certificate. This was especially the case in more remote countries.

"Anywhere that's not a first world country - you would come up with questions," she said.

She also recommended that families travel with an e-file with everything on it in case they are challenged.

One final suggestion is to speak to the airline you are flying with to seek advice.

Have you ever encountered problems like this while travelling with your children?