Question for anybody adopted out there!

Today my mother asked me if I wanted to know who my biological mom is. I've been alive 21 years, and have never really cared enough to know. My family is good enough for me. We were having a conversation about health, which is why the question arose. I said I wasn't sure how to answer, so she proceeded to tell me she knows that my bio mother was recently diagnosed with a thyroid issue (which could explain my unexplained weight gain.) Now, I'm one of those people who gets stuck on things for a while. As much as I couldn't care about knowing, and I really don't want to know, there's a little part of me that does. So I ask, would you want to know? What would it change? Why would you want to know? Would you try to get to know them? Do you think it would hurt your parents feelings? It's a lot of questions I have, and I feel like even if I did know, I don't think I would ever want to talk to her. I love my *adoptive* mom. I've just considered them my real parents for my whole life, it's never really bothered me until the question came up today.