This does not make any sense. Did you read the lists people have made? They include things like: work for a long time in the same lab during undergrad, work with a generous professor, take on a project that has already been started, take initiative, have luck, be competent, work hard to understand the science... all of which I agree with. Nowhere has anyone added to that list: have doctors for parents. If you, personally, are URM or low SES and are making excuses for yourself, please refrain from generalizing to others.
I am from a low SES childhood. My father is a car mechanic and my mother a secretary, they are divorced. First generation college student and all that.... I got my initial research experience by personally applying to REUs that gave stipends.
I also currently have three publications. Two were published during undergrad: one co-first author in a low tier genetics basic science journal, one second author in a German journal where I designed the experiment 100% and collected 4/5 of the data.
If you are REU or low SES, please be proactive and do not allow yourself to feel like you can't do something due to the educational background of your parents. Maybe that was true 20 years ago, but in this technological age, there is no excuse for ignorance. Talk to your pre-med adviser, use SDN wisely, speak with your peers. You might learn that: you can make $3,000 in an REU over the summer, you can sometimes apply for work/study at your school for working in a lab, you can sometimes take "lab research" as a credit in school. With these options, a low SES student would still have time to work outside of school and could to an REU in the summer to earn money (that's what I did). As for a URM, there is no excuse. Since it has nothing to do with the information your parents provide you (internet/take initiative/pre-med adviser), there is no reason that I can think of that a dedicated URM could not do this. It is all about informing yourself and taking initiative!
I just wanted to add my two cents. Please people: do not be discouraged. Remember that this is a learning process and that getting a publication is not a ticket into medical school, nor is it necessary or even common in other applicants.
Do research, learn something, publish if you can, reflect on what you did. Don't let anyone tell you that you can't do 3/4 of those things just because you are URM/low SES.
Best,
C