If attributes such as age or gender are strong features for certain dependent variables that improve the predictive performance of a model, then it must be allowed to use these variables. For example, it is well known that colorectal cancer is more prevalent in men over the age of 50 - so a statistical model used to allocate free colorectal exams would favor old men. Is that discriminatory? Likewise, for any given variable, one will find certain features that favor men or women, young or old; finding these dependencies is precisely the point behind statistical models.