To quickly summarize a discussion on the Stata Blog (here), for those seeking to test whether coefficients for two independent variables in the same regression estimation systematically differ from one another, the basic coding structure follows:
reg a b c
test b = c
A resulting F-test statistic that falls below your significance threshold implies that the difference between the coefficients for independent variables b and c is significant. Obviously, a suite of other post-estimation commands also exists for a host of other issues.