Recent research has made strides toward fair machine learning. Relatively few datasets, however, are commonly examined to evaluate these fairness-aware algorithms, and even fewer in education domains, which can lead to a narrow focus on particular types of fairness issues. In this paper, we describe a novel dataset modification method that utilizes a genetic algorithm to induce many types of unfairness into datasets. Additionally, our method can generate an unfairness benchmark dataset from scratch (thus avoiding data collection in situations that might exploit marginalized populations), or modify an existing dataset used as a reference point. Our method can increase the unfairness by 156.3% on average across datasets and unfairness definitions while preserving AUC scores for models trained on the original dataset (just 0.3% change, on average). We investigate the generalization of our method across educational datasets with different characteristics and evaluate three common unfairness mitigation algorithms. The results show that our method can generate datasets with different types of unfairness, large and small datasets, different types of features, and which affect models trained with different classifiers. Datasets generated with this method can be used for benchmarking and testing for future research on the measurement and mitigation of algorithmic unfairness.