Sure, but keep in mind that there will be plenty of students applying who weren't fortunate enough to land in a functional family situation and by painting your childhood as dire you may be compared to them. Another pre-med in this thread doesn't seem to grasp that this could actually hurt you if not done very, very carefully. If you want to write about your experience pre-age 7, go ahead and do so, but I caution you against using those years as a means to get an advantage with your application, which your initial posts have indicated is exactly what you're trying to do. Just be aware that since you were adopted and raised by stable parents, it could come off in poor taste to then turn around and paint your childhood as largely deprived, especially if you were adopted into a relatively high SES.
You can write about it as more of an interesting fact rather than an attempt to get sympathy points or an advantage and still get your point across.
To give you an anecdote, one of my best friends was adopted from Russia when he was between 6-8 years old (I don't remember exactly the age). He only remembers very, very basic Russian and won't claim that he knows it at all. He identifies as American. He was adopted into a pretty well-to-do family and hasn't looked back. He performed well in high school, took plenty of AP courses, and went on to do very well in college. His first few years in a Russian orphanage never come up. Ever. So I apologize if I've offended you, but I find your sudden interest in using this adoption to paint your early years as disadvantaged to gain an advantage as...odd. And as someone who applied as very disadvantaged, I find if off-putting that someone whose childhood was largely stable and well-resourced would try to get an advantage on their application.[/QUOTE
Your feedback is very helpful. I questioned this scenario because I wasn't quite sure about it. I really don't think it's unusual. I feel like it's important, and there has to be a story about it; the past developed me. I'll just have to write my past experience very informative, and cautiously well written. More than likely to be on the safe side, just state it as a fact like you mentioned. That's awesome of your best friend. Just curious, did he also attend medical school after undergrad?