Whether a person is gay or not depends on who they are attracted to sexually. The Bible, for example, contains proscriptions against sexual acts, not sexual orientations.
Traditional Christianity is restrictive of sexual conduct in general, and does put same-sex attracted persons at a disadvantage with respect to being able to have a morally acceptable sex life. Some Christians are not fully traditionalists on sexual issues, however. However, it is a mistake to say that Christianity teaches that there is something wrong with being gay. It doesn't say that at all.
To this is can be replied that not only sexual acts, but the lust for them, can be sinful. However, because Christianity makes a crucial distinction between temptation and sin (Jesus experienced the former but not the latter).
In fact, if you take literally the statement that Jesus was tempted in all things just as we are, (Heb: 4:15), then we have to conclude that the Bible teaches that Jesus was bisexual. He experienced temptation both to hetersexual sin and to homosexual sin, so he had to have been bisexual. QED.