A big question that comes up often, both online and in real life: How can non-minority allies cultivate and retain minority students into the sciences (or any of the other STEM disciplines?
The truth is, the answer is to make the education experience relevant and welcoming. Easier said than done. For one reason is that relevance and what one defines as welcoming are not universal concepts. Very simple reactions can come across as coarse and turn students off. For example, an instructor's reaction to students' questions in an introductory course. While an undergraduate I once asked the biochemistry professor to repeat what he said as he pointed to a diagram. He proceeded to blast me for not recognizing his short-hand and remembering each & every amino acid from the first day of class. The rest of the class then looked at me like I was an idiot. I felt like one, too. I didn't feel like I could admit to 'not knowing' and was definitely to embarrassed to study with the other students in the class whom I was convinced were all much much smarter than I was. I failed that course; and I hated that professor with a purple passion. I still can't stand his smarmy ass. (Hope he's dead.)
I look back now and realize it was his way and so many science professors behave similarly to most students. But I really got the impression that they were especially impatient with students of color (Black or Latino, that is, not Asian students), athletes and those from large metropolitan cities (which were often Black students). Whenever, some of us would study together or when upperclassmen interacted with lowerclassmen we often shared similar stories of the same professors.
My point is that being a prick may be part of academic culture, but it also one reason for minority students switching paths and changing their majors. I think this may be particularly problematic for sensitive students who've been dealing with a lot of insecure chatter - either in his/her head or whispered in hallways or blatantly expressed by guidance counselors, TAs, professors, or other students.
I call them the "You Aren't Supposed to Be Here" demons.
My first round of advice is this: Don't be a prick, even unintentionally. By that I mean don't tell someone their struggle isn't real or dismiss them. Studying is hard, so is balancing work-life issues. I'm not saying you should be their sounding board and excuse them. No, not at all. But I am recommending treating students like they people and not scum on your shoe. This stuff we call science may come easy or quickly for you, but some students may have to struggle to get the info. Point them to university resources to help them study. No matter how odd or unbelievable or unlikely you think these confidence-conflicts may be, the sure fire way to turn a student off to the discipline (and to you) is prove that you can't be trusted to take his/her concerns for doing well seriously.
Not every professor is a nurturing type, but is it really too much to say, Hey, I think you can do it. Be sure to come to class, form a study group, and don't be afraid to ask a question?
It comes down to definining what kind of ally you will be. Are credibility and authenticity necessary for mentoring minorities? No, not at all. Almost all of my mentors in science have been white males and females. So, you don't have to be exactly like the students you mentor to usher them into this discipline. However, I believe empathy is a bit easier for people who have something they can relate to in students. Perhaps that's why females or persons from other marginalized groups (e.g. Jewish ancestry, immigrant families, first generation college attendees,) are often the professors who call attention to diversity issues at pre-dominantly white and/or male departments and call for a change.
I recommend everyone exercise their empathy muscles more. That's because as we work to knock down barriers for one group, say African-American and Latinos, we realize there is still much work to do. I've had my eyes opened to the paucity of representation of Native American Scientists and Engineers in the blogosphere and at scientific conferences as well as to the work needed to make Lesbian, Gay, Bisexual and Transgendered (LGBT) professionals and those with disabilities feel more included in STEM. So our work may never be done, but we're still making strides.