Ever since i was little, i was different. My parents are fair(but not literally white we are asians) and i'm a bit darker. i don't know i never really considered the idea of me being adopted but, sometimes i wonder why. I look nothing like my father, and i have few features inherited from my mother like the hair type. Trust me on this, my mother have never been with a different man, like ever. My siblings also, they're fairer and they look alike, and somewhat i'm different. i don't know? i'm just confused and stuff. if ever they tell me i'm adopted i won't get mad at them, i'm mature enough to understand. i just need your opinions on this.
I'm adopted, but it was just a fact I grew up with since as early I can remember. If you have questions for your parents, mindfully tell them how you feel. If they say you're irrational, I would suggest you tell your parents to get a test done so they can prove you're being irrational. If they refuse a test repeatedly, I would be more curious into why they would refuse it...
You could always ask. The family connections are there, and you know and are mature enough to know that they're your parents adopted or not. Perhaps ask, and include the above. They likely will say no you're not adopted, but could potentially surprise you. This said, many children look different from their parents. I look similar to my mother, but nothing like my father, as an example.
I look absolutely nothing like my family. My father and brother both have really curly almost black hair, and I hear my mother had dark brown, and I have straight light blonde hair (which I just recently dyed). My features are softer, and really the only commonality is my father, brother and I all have blue eyes. We look so little alike I get mistaken as being the girlfriend of either my father or my brother constantly. And I know for a fact that I'm not adopted. So, sometimes it works like that. But I would suggest maybe mentioning the possibility to your parents, like the two before me suggested, and see how they react.
I know these two siblings. One has straight blond hair, blue eyes, fair skin, etc., and the other has curly brown-almost-black hair, dark skin, brown eyes. They don't even look the same race and neither look like their parents, but they are all related. It's really strange. Would your doctor know?