The Black Mage could be either gender, really. I always thought BM was male and WM was female, though maybe that has something to do with how the 8-Bit Theater shows the two. However, if you press Auto-Select on the names in FF1 DoS, the game can come up with both male and female names for the Black Mage. As for other classes, I think White Mage had mostly female names, Thief and Red Mage had at least one female name (Daryl and Lola), and neither Warrior nor Monk had any female names.