How to find a cofounder — and build a strong partnership — according to people who've done it

Technical.ly

26-06-2025

Where do you find the perfect cofounder?
For HeadStrait Labs' Alyssa Theroux, 23, and Mary Squire, 25, it was across the classroom.
The duo met during their first semester in the biomedical engineering program at Carnegie Mellon University and quickly bonded over their shared enthusiasm and active participation in their medical device class.
'Throughout the semester, we started sitting closer and closer together,' Squire told Technical.ly, 'and by the final project, we were like, 'Do you want to be partners?''
That partnership paid off. Theroux and Squire won their class's final pitch competition in 2022, and that project became the basis for HeadStrait Labs, their Pittsburgh startup developing a head stabilization device used in emergency response, sports and military settings.
'The current cervical spine and mobilization devices that are used today are really outdated,' Theroux said. 'If you suffer a C-spine fracture or injury, any small movement could affect that significantly, and it can lead to secondary injuries. That really drove our passion for EMS.'
Two years later, HeadStrait Labs' neck brace, called the EVAC-1 with SMARTmotion, has earned some serious local recognition. The company has raised $100,000 from the Robotics Factory accelerator program, another $100,000 from the Tartan Entrepreneurs Fund and $25,000 from the Re-Impact Awards. Those wins landed it on Technical.ly's 2025 RealLIST Startups earlier this year.
The device is already being tested by Oklahoma State University's football program, and HeadStrait is now recruiting participants for an upcoming clinical study with Pittsburgh's largest healthcare provider, UPMC, Theroux said.
Theroux and Squire credit their shared work ethic and mutual trust for keeping their partnership strong.
'I know this type of partnership doesn't work for everybody. We've lived together, gone to school together, run a company together — all at the same time,' Squire said. 'So we're very good at making joint decisions. We literally have a legal document that has a tiebreaker if necessary, and in two years, we've never once exercised it.'
Still, they face the realities of building a startup as women founders in a male-dominated industry. Sexism persists in the startup world, with female-only founded companies raising just 2% of VC funding last year, according to research from PitchBook. This is dramatically lower than the 20% of VC funding that went to startups cofounded by men and women together.
In this edition of Technical.ly's How I Got Here series, Theroux and Squire share how they've built a strong cofounder relationship, the lessons they've learned navigating early-stage entrepreneurship and what it takes to break into an unequal field.
This Q&A has been edited for length and clarity.
What's the secret to a strong cofounder relationship?
Theroux: Communicate, communicate, communicate. And let the other person work to their strengths, so that you don't have to work so hard to overcome your weaknesses. Divide tasks so each person can shine and move the company forward.
Squire: We were lucky enough that the environment we were in, studying for a master's in biomedical engineering, you had to be a certain level of interested in this space. So that was an instant filter for us, which was a lot easier than trying to find someone on the street who's aligned with you.
Look for someone with the growth mindset. Being aware that that person's willing to grow and adapt in every aspect of life means they're probably going to do a very good job of that in this industry too.
What advice would you give other female founders?
Theroux: Don't let the statistics get in your head. Shoot for the moon. You'll land somewhere in the stars. No matter what you know, no matter what other people think, you have to believe in yourself and your partnership. You and your cofounder have to move as one unit. And find a good support group.
Squire: Share your opinion, especially in a male-dominated industry like engineering or the startup world. Being a young female entrepreneur is a hard position to be in, and I've noticed that the times I have shared an opinion or a perspective, it's unique because no one else in the room is really sharing that one. So even if it's not the most beneficial or the correct answer, it's probably gonna provoke thought amongst everyone else, or at least get people in a mind space they probably weren't already in.
What's been the biggest surprise since becoming a startup founder?
Squire: We've both been in very competitive environments, from the level of sports we played, to the schools we've gone to, to the degrees we've done, and we've excelled at those things, but there's lots of rejection that comes along the way. Despite that, I don't think I anticipated the level of nos you're gonna get in this process. It makes the yeses very exciting, let me tell you, but the number of nos you get, I think, it's been more than I expected.
But, every no is actually more helpful than a yes, because you know what you need to change. If no one ever gives it to you straight, you don't really get to make improvements.
What opportunities would you recommend to others?
Squire: When you do have the capacity to go to an event where you can learn something, you should go. We do this thing called 'our one positive,' so even if it's the most boring event or we had a bad time, we ask, what was the one thing that we did take away? It's funny, half the time it's the same takeaway for both of us, but that always makes it feel like what we're doing isn't a waste of time.
Theroux: Networking is really important, but there's always a balance to it.
What's the biggest challenge you've had to overcome so far?
Squire: Balancing feedback, deciding when to take it and when not to. We're like a sponge. We like to take it all in, but it gets to the point where feedback is actually contradicting, and if you don't choose one, you're not actually going to make progress.
Theroux: You have to filter feedback through your own knowledge and experiences, and then at some point you've got to take the lead and see what happens. We've made a really big effort to take responsibility and ownership of the choices that we make. Jump into it and make sure all parties are aligned before you do it.