Some are, many are not. It all depends on the individual. Some bi people are more romantically attracted to men and more physically attracted to women. Some bisexuals are attracted to people who conform to mainstream gender norms; some are attracted specifically to people who defy those norms. For some bis, gender is an important part of attraction. For other bi people, it is totally irrelevant if a person is male, female, intersex, or something else. Many bis have very fixed patterns of attraction, while for others, the balance between heterosexual and homosexual attraction is fluid and changes over the years.