I'm aware of what it looks like, and I've been up at 12-15% before. It's absolutely genetic, most of my family runs very skinny. I have generally decent muscle definition, although the fat I have tends to sit in my hips and shoulders. My doctor suggested I might have less interstitial fat than most people, which explains a few other health effects.

I'm not bragging, there are serious downsides, but it's absolutely possible to sit at 10% year-round, just not while maintaining any serious level of elevated muscle mass.