This study reports findings of the gender differences within a pair programming context. A large pool of university computer programming course undergraduate and graduate students was paired into three distinct pair categories: male-male, male-female, and female-female. All pairs performed pair programming tasks under a controlled lab environment. The pairs' final outputs in the categories of code productivity and code design were quantitatively measured, and the post-experiment questionnaire was also measured. The results revealed that the male-male pairs had the highest scores and female-female pairs had the lowest scores in both code categories, but not significantly. In the post-experiment questionnaire, the communication and compatibility levels showed significant differences between the three different pair categories. The male-male, female-female pairs or same gender pairs had significantly higher levels than the male-female or mixed gender pairs. Additionally, the female participants particularly voiced genderbiased concerns about collaborating with male partners in doing the pair programming task.