There has been very little research on the effect ethnicity, culture, socioeconomic status, or urban/suburban/rural lifestyles have on ODD. Demographics on age and gender are known: ODD affects more boys than girls until puberty, and then affects the genders about equally.
ODD and Boys
Before puberty, ODD is more common in boys. Not surprisingly, so is ADHD, so if you have a young son who has ADHD, you'll need to look carefully at his behaviors and consider the strong possibility that he could also have ODD.
Though the rates are about equal after puberty, the types of defiant behaviors vary widely between boys and girls. Boys typically will display more confrontational and aggressive behavior as part of ODD. And, sadly, more boys are found to have CD, so if you have a boy, you'll need to work quickly to make sure his behavior does not develop into CD. When you enlist the help of a professional, share your concerns about ADHD and any worsening behaviors that could point to CD.
ODD and Girls
Parents of girls who have ODD may feel especially frustrated because ODD behaviors are not considered very feminine. Acting out, defying adults, losing her temper — these behaviors aren't considered “ladylike” or “sugar ‘n’ spice.” Admonishing your daughter to “be nice” and behave “like a young lady” are probably not going to be effective at fixing her behavior, and could even cause her to question her identity as a girl. For example, if your daughter often swears at you, and you usually tell her that she's not speaking in a very ladylike way, after a while she might conclude that she must not be very ladylike. It will be better for her in the long run to focus on her specific behaviors, as your therapist will probably suggest, rather than on labels or societal expectations. It could also help if you are careful not to set a double standard for your daughter and any boys in the house; if boys are allowed to swear and she isn't, then she could become more angry and frustrated.
Though there is not enough data to make a strong case, aggressive, confrontational behavior in girls could be rising with the popularity of “girl tough.” In other words, if it has become more socially acceptable for girls to be aggressive, you may begin to see defiance manifested in more confrontational and aggressive behaviors in girls than you did when you were a child.