Two Nerds, One Pheromone Study, Zero Chill

A DNA Test That Doesn’t Just Tell You You’re 12% Neanderthal

Jess Davis is a bartender with a music degree she’s not using, a father in prison, and exactly the kind of chaotic-but-lovable life that romance heroines get assigned when the author needs someone scrappy and sympathetic fast. Enter Fitzgerald “River” Peña, tech founder of GeneticAlly, a company that claims it can find your perfect romantic match through a saliva sample and some very confident proprietary algorithm. Jess gets roped into being a guinea pig for the launch, mostly because River needs a “regular person” success story and she needs the appearance fee. The twist, because there’s always a twist, is that her actual match in the database isn’t the charming billionaire-adjacent scientist standing right in front of her looking at her like she hung the moon. It’s someone else. Someone she has to go on record-breaking dates with while River watches, in increasing states of denial about his own feelings.

Look, I know how this sounds. I know “DNA matchmaking startup” sounds like the premise a rom-com generator would spit out if you fed it Silicon Valley and The Bachelor. But Christina Lauren commit to it hard enough that it works. They actually build out the pseudo-science, they give River an origin story for the company that’s more emotionally loaded than you’d expect, and the structural gimmick, Jess dating her “genetic match” while falling for the guy running the whole experiment, gives the book a clean, propulsive engine. You know where it’s going. You want to watch it get there anyway.

Where It Sings, Where It Wobbles

Here’s the thing about Christina Lauren as a writing duo: they are, hands down, some of the best banter writers working in romance right now, and this book is proof. Jess is funny in a specific, lived-in way, sharp about her own bad decisions, self-deprecating without being a doormat. There’s a scene fairly early where she’s bartending and has to fake her way through small talk with a customer while simultaneously texting River in a full panic, and the dual-track comedy of it, calm professional Jess versus internal-meltdown Jess, is genuinely one of the funniest bits I’ve read in the genre this year. The chemistry between Jess and River has that effortless, low-stakes-banter-that’s-actually-high-stakes quality that Christina Lauren do better than almost anyone. When they’re just talking, trading jokes, avoiding the thing they’re both clearly feeling, the book is a delight.

But I have to be honest about the back half, because the plot mechanics that make the setup so fun start creaking once the story needs an actual conflict to sustain itself for three hundred more pages. The whole “matched with someone else” storyline requires Jess to keep dating a guy who is, structurally, filler, and the book knows it, which makes those scenes feel like exactly what they are: a device you have to sit through until the real relationship gets cleared to happen. There’s also a plot thread involving River’s business partner and some ethically shady stuff with the algorithm’s data that gets introduced with real weight and then resolved so fast I flipped back a page to see if I’d missed something. I hadn’t. It just needed to be dealt with so the wedding-adjacent ending could happen on schedule.

I’ll admit I went back and forth on how much to ding it for that. Part of me wants to say a rom-com doesn’t need airtight plotting if the two leads are this fun together, and mostly I believe that. But I’ve also read enough Christina Lauren to know they’re capable of tighter structure than this (The Unhoneymooners holds together so much better), so when The Soulmate Equation gets baggy, I notice it more than I would in a lesser writer’s book. Maybe that’s an unfair standard. Maybe I just wanted the algorithm subplot to matter as much as the romance did, and I was always going to be disappointed there.

The father-in-prison material is handled with more restraint and sadness than I expected going in, too, which is worth naming. It’s not played for cheap sympathy or resolved too neatly. That’s the kind of small choice that made me trust the writing even when the plot mechanics were straining.

The best rom-coms aren’t about whether the algorithm is right. They’re about watching two people decide they don’t care what the algorithm says.

About Christina Lauren

Christina Lauren is the pen name for Christina Hobbs and Lauren Billings, two women who met on a Twilight fan fiction forum, decided their shared brain cell was strong enough to co-write professionally, and have been doing it ever since with an output that should honestly embarrass solo authors. They’ve written new adult, they’ve written thrillers under the radar, but they made their name and their empire on contemporary rom-coms with a very specific house style: fast banter, high-concept hooks, and a willingness to let their heroines be a little bit of a disaster. If you’ve read The Unhoneymooners or Roomies, you know the rhythm already. The Soulmate Equation is them doing what they do best, dressed up in a lab coat.

If the Banter Got You, Read These Next

If you want your own copy to underline the funny parts, it’s here, but if you’re building a reading list after finishing it, here’s where I’d point you.

The Unhoneymooners by Christina Lauren, for the tighter plot and even funnier fake-relationship premise, this is the one I’d hand someone who wants proof of what this duo can really do. The Kiss Quotient by Helen Hoang, for another book that uses a slightly clinical, structured premise (this time neurodivergence and paid companionship) to build real emotional stakes. Beach Read by Emily Henry, if what you actually wanted was the banter-plus-heart combo without the sci-startup scaffolding. The Hating Game by Sally Thorne, for pure enemies-to-lovers workplace tension if River and Jess’s slow burn was your favorite part.

For your book club

1. Do you think the DNA matchmaking premise is a clever metaphor for how we actually fall in love, or just a fun gimmick the plot needed to justify itself?
2. Jess spends most of the book technically dating someone who isn’t River. Did that storyline work for you, or did it feel like a delay tactic?
3. How did you feel about the way the book handled Jess’s father? Did it earn its emotional weight or did it feel underexplored?
4. The ethical subplot around GeneticAlly’s data gets resolved very quickly. Would you have wanted more consequences, or did you not care because you were there for the romance?
5. If a real version of this algorithm existed, would you take the test? Would you trust the result over your own gut?