Equity in the classroom

I've been thinking about how best to discuss the issues of equity in the classroom with pre-service teachers. Some people aren't aware of myriad of issues that exist when one is placed in a diverse population of students (some people still grow up in homogeneous environments). What would be the best way to discuss this in a methods course? I have a classroom episode that involved ESL students which I think would be good to discuss, but there are plenty of other things I would like them to think about, such as cultural and socio-economic backgrounds, gender, disability, different learners.... So, do I just try to weave that into the course as it goes on and not talk about it in one spot concentrated, rather keep coming back to it throughout the year?