Mike O’Brien says he always knew he wanted to be a dad. But he never met the right partner. 

“I thought maybe that's never going to happen, so if I want kids, I just need to do it myself,” he says. So in his mid-40s, while serving in the Army as a public affairs specialist, he decided he wasn’t going to let his dream slip away. He chose to pursue surrogacy as a single father. 

Building a family on the other side of the globe

When O’Brien started his surrogacy journey, he was stationed in Germany. The more he researched, the more he realized that egg donation and surrogacy were more affordable in Europe than in the United States. So he found an egg donor in Ukraine and a surrogate in Poland — and in early 2020, at which point O’Brien was stationed in Italy, Charlie and Ellie (now 6) were born.

“It was the beginning of COVID so I had three months paternity leave as a single dad,” he says. “And then when paternity leave ended, lockdown started in Italy, and so that was another three months. So the first six months, you know, I got to stay home with the kids and learn how to do all that stuff. And that was great.”

O’Brien enjoyed being a dad to Charlie and Ellie so much that he wanted to have even more children. Using the same egg donor and a different Polish surrogate, he had his second set of twins in late 2023: Mattie and Maggie (now 2). This time around, O’Brien was stationed in Washington State. He took three months of leave, then had to return to work.

Luckily, O’Brien says his fellow servicemen and women, including his boss, were all incredibly supportive. 

“They were all offering to babysit and bringing over meals at the beginning,” he says.

Driving into the family's next big chapter

Then on Feb. 1, 2025, at the age of 53, O’Brien officially retired from the military after 29 years of service. While many people spend years planning what retirement will look like, O’Brien already knew exactly what he wanted his next chapter to be.

More time for bedtime stories. More mornings without rushing out the door. More chances to watch his little ones discover the world.

So two days after retiring, O’Brien, his two sets of twins, and their dog set out on their next adventure: driving along the Pan-American Highway in their camper. Their plan was to go all the way from their home in Washington, to Argentina — about 16,500 miles long. The family of five (and dog!) made stops at Disneyland, Rio, the Galapagos, and more… and finally got to the bottom of Argentina on Dec. 6, 2025. At that point, O’Brien and his family turned around and drove back up the east coast of South America.

Like any parent will tell you, life with four young children is equal parts joyful, exhausting, messy, and magical — even if that life is on the road. And that's exactly how O’Brien likes it.

His older twins attended local schools in Guatemala and Peru, picked up Spanish, and embraced experiences that can't be taught in a classroom. Along the way, the family discovered breathtaking landscapes, unfamiliar traditions, and plenty of everyday moments that stretched everyone's comfort zone.

Their next stop? New York City, where O’Brien will be attending Columbia University for degrees in Spanish and film. His children, for their part, will be entering first grade and daycare.

For trips like theirs — or traveling with kids in general — O’Brien suggests creating an itinerary but staying open to change. 

It’s a perfect metaphor for parenthood: Plans are fine as long as you’re willing to adapt. You really don’t know what parenting, what life, is going to be like, O’Brien says. “And I'm just so pleasantly surprised.”

Sam Brodsky Falcone contributed to this article.