theorists stress that schools are agencies for perpetuating social inequality because parents with limited income are not able to provide the same educational opportunities for their children as are families with greater financial resources.

Explanation:

Conflict theory was presented by Karl Marx, he said that the society is always in a state of perpetual conflict due to limited resources and that the social order is maintained by power and domination.

According to this theory people with power and wealth try  to hold on to it by every possible means.  

So the conflict theorists do not believe that public schools can reduce the social inequality, but they  believe that the educational system perpetuates and reinforces the social inequalities caused due to differences in race, gender, ethnicity and class.

use this site