If the creature in Frankenstein has a gender, why is it male?I think it may be reflective of the superficial, patriarchal society of the time, but I am not sure.
I don't think there is a feminist angle to this novel, or at least not the angle you are suggesting. Dr. Frankenstein had to put a body together out of parts he dug up. He would be more likely to work with male body parts because he wouldn't want to create a female monster, and he certainly wouldn't want to create a hermaphroditic monster by mixing up a lot of different parts. In fact, I believe the monster wanted to force him to create a female mate for him and he refused.
I believe that Mary Shelley had an unconscious or subconcious theme in mind when she wrote the story. She was implying that men have no business trying to create living human beings; that is something that only women can do and something that only women should do. If a man tries to create a human being he will end up creating a horrible monster. That seems like a better feminist angle than arguing that Frankenstein should have created a female monster--or that he was showing male chauvinism by creating a male monster.