Every couple deserves
to know before they grow.

Why we exist

For most of history, people married someone from the next village, and the next village knew exactly who everyone's cousins were. Families built systems to avoid marrying close relatives: gotra and sapinda rules, family registers, matchmakers and very well-informed aunties. Some communities, like those served by Dor Yeshorim, went further and checked couples for hidden genetic conditions before they married.

Today you can meet your person on an app, in a city neither family has lived in. Sperm donors can have dozens of children. Adoption records get sealed and family stories get lost. "Not to my knowledge" is the honest answer most couples can give, and it isn't enough.

Meanwhile, total strangers can carry the same silent gene for conditions like cystic fibrosis, spinal muscular atrophy, sickle cell disease or thalassemia. Most carriers have no idea until they have an affected child.

DNA can now answer both questions quickly, privately and affordably. We exist to make that knowledge normal, the way a blood-group check before marriage is normal in some countries.

What we believe

• Informed choice, never judgment. We will never tell anyone who to love, marry or have children with. We give couples clear information and leave every decision to them.
• Privacy by design. Our relatedness check runs on your own device. Your DNA never reaches us, so we can't lose it, sell it or be forced to hand it over.
• Evidence, not fear. We cite research and professional guidelines, give real numbers including the reassuring ones, and don't use scare tactics.
• Respect for every culture. Traditions like gotra, kundli and family registers grew from real wisdom about family and health. We explain where DNA adds to them, without mocking anyone's beliefs.
• Everyone, everywhere. Our tools work in any country, and we're building carrier-check options region by region.
• Humor with care. We joke about cousins and aunties. We don't joke about people's health, disabilities or painful family discoveries.

What we offer

• A free DNA relatedness check that compares two raw DNA files in your browser.
• Couples carrier-check requests, with options, pricing and next steps for your region.
• Free tools: the cousin calculator, the shared cM calculator and cousin marriage laws.
• Plain-English guides to cousins, shared DNA and genetic screening.

How we make money

Our tools and guides are free. We may earn affiliate commissions when you buy a DNA kit through our links, and we plan to charge for some services, like the carrier check, with the price shown before you pay. Money never decides what we write or recommend. See our editorial standards and affiliate disclosure.

Who we are

Don't Marry Your Bro is made by Lotusbud LLC, a small team based in the United States. We're building a panel of genetic counselors to review our health content. If you're a genetic counselor, clinician or researcher who'd like to help, or you've spotted something we should fix, we'd love to hear from you: founder@dontmarryyourbro.com.