There’s an interesting site, though it’s such a depressing topic, called Gendercide that has some intelligent discussion of so-called honour killings, as well as a fair amount of other information about killings where the gender of the murdered person is a main factor.

Sometimes, men are also killed for being men, as in Iraq under Saddam, where Kurdish men were seen as potential future fighters and killed.

In fact, whether you are male or female, Iraq must have been close to the worst place to live on the face of the earth for a couple of decades now. (This appears to go double if you are Kurdish.)