AITAH for Ruining My Family’s Peace with a DNA Test?

I (26F) thought I was being fun and quirky by giving everyone in my family DNA testing kits as Christmas gifts last year. I’d seen people do it on TikTok, and the idea of uncovering our ancestry or finding out weird family traits seemed like an exciting bonding experience.

Everyone laughed when they opened their boxes, and we spent the morning joking about what we might discover. My dad teased that maybe he’d turn out to be 1% Viking. My mom said she’d probably be boringly Irish through and through. Even my older brother (29M), who’s usually grumpy about these things, agreed it was a neat idea.

Fast forward a couple of days, and the results started trickling in. I got my notification first turns out I’m 48% German, 32% Irish, and some bits of other stuff sprinkled in. I shared it with everyone in the family group chat, and they all seemed eager to compare.

That’s when things got… weird. My brother didn’t say much when his results came in, but he did make a comment about being “a lot less German and Irish than he expected.” My dad, on the other hand, got noticeably quiet after seeing his results. He didn’t even crack a joke about Vikings like he said he would.

Eventually, my mom asked him what was wrong, and he just blurted out, “The math doesn’t add up.” He showed us his ancestry breakdown, which was very heavily German, and none of that aligned with my brother’s . My brother’s results, on the other hand, had a significant amount of Italian which was also nowhere in my dad’s results.

The room went dead silent. Then my mom, looking flustered, said something vague about recessive genes and everyone having unique DNA. My dad didn’t seem convinced. Later that night, I overheard him pressing her about it, and things escalated. Long story short, she admitted that my brother was the result of an affair she’d had years ago, but she’d thought it was irrelevant since my dad had raised him as his own.

The fallout has been devastating. My dad feels betrayed and says he can’t trust my mom anymore. My brother is struggling with the idea that the man he always thought was his dad… isn’t. My mom has been begging me to “fix” things, saying that this never would’ve come out if I hadn’t insisted on the stupid DNA kits. She claims I’ve ruined their marriage and our family’s peace.

My dad has moved into the guest room. My brother won’t even talk to me because he says I started all this drama and made him question his entire identity.

I genuinely didn’t mean for any of this to happen. I thought it would be a fun, lighthearted activity. But now I’m wondering if I was being selfish or careless by not considering the potential consequences. AITAH?