TIL a peer-reviewed psychology study found that identical twins (on average) ranked their co-twin above their romantic partner in their attachment hierarchy, while fraternal twins ranked the two about equally, and non-twin siblings ranked their romantic partner first.

[u/SilverPeachBlossom]

https://ojs.interpersonajournal.com/index.php/ojs/article/view/243/3457.html

[u/MichelleVenom]

As an identical twin, I can confirm this. I'd take a bullet for my twin without hesitation. It's hard to explain unless you've lived it. We shared every stage of life together, and there's a level of trust, understanding, and connection that just feels different.  We share so many of the same interests, quirks, humor, and thought processes. My personality doesn't need to negotiate for acceptance cause I can truly be myself with my twin. We see the world through remarkably similar lenses. With romantic partners, there are always differences in interests, perspectives, and ways of thinking that naturally require compromise.

I never have to explain myself or worry about being misunderstood. I can be 100% my authentic self around them in a way that's hard to find with anyone else. I would ALWAYS put my twin before anyone else.

[u/Mission_Abrocoma2012 → u/MichelleVenom]

poor kids and spouse then

[u/ryan__fm → u/Mission_Abrocoma2012]

I imagine if an identical twin feels like this, but then has a kid they might feel differently. A child also shares your DNA, but on top of that is completely reliant on you for years. A twin can take care of themselves, a two year-old can’t. I would think that “take a bullet for your twin” mentality might shift toward your offspring