What Is Wrong With Homosexuality?

So, what exactly is wrong with homosexuality or homosexual acts? Or more specifically, since this is a Biblical/Christian theology blog: Does the Bible or the church teach against homosexuality or homosexual activity? If so:

• Why does it do so?
• Is it right for it to do so? and
• Do or should such teachings apply to us today, and if so, how?

Before you answer these questions, please first consider and answer these additional questions (Note: I am using "homosexual" and "gay" to refer to either males or females):

I. Is simply being homosexual or having same-sex attractions wrong? If yes, please explain why.

II. If not, then is it the sexual behavior between two persons of the same sex that is wrong? If so, why is that:

1. Is it because the only proper sexual activities between two persons are those that directly or indirectly include both one and only one penis and one and only one vagina? If so, what about sexual activities between two persons when one or both of them has had sex-reassignment surgery so that now one of each sex organ is present even though one or both of them previously had the opposite sex organ?
2. Is it the inability or failure to consummate the actions with coitus (i.e., penis-vagina intercourse) that makes same-sex sexual activities wrong, since except for coitus two women or two men can together do just about everything sexually that a man and a woman can do? If so, what does that mean for deliberate non-coital sexual activity by heterosexual couples, or for heterosexual couples who do not or cannot (due to disability, etc.) consummate all their sexual activities with coitus?
3. Is it because the potential to produce children is what makes marriage and instances of sexual activity okay? If so:
   1. What does that mean for heterosexual couples who use natural or artificial methods to prevent unplanned or unwanted conceptions?
   2. What does that mean for sexual activities between heterosexual couples who cannot or who cannot any longer have children? Consider the following scenarios:
      • A couple discovers before they're married that they won't be able to have children. Should they be able to get married, and if so, should they be able to engage in sexual activities after marriage for the pleasure of it and the oneness and companionship and intimacy and love it engenders and enhances between them so they become more giving and fulfilled human beings, even though they know that no children can result from such activities?
      • A couple discovers after they're married that they physically can't have children, and despite many prayers and clinic visits, neither God nor doctors heal their infertility. Can they continue to engage in sexual relations for the pleasure of it and the oneness and companionship and intimacy and love it engenders and enhances between them so they become more giving and fulfilled human beings, even though they know that no children can result from such activities?
   If potential childbearing is not the reason for marriage and instances of sexual activity, can two gay persons who have not been changed from their homosexuality (whether they cared to change or tried to change or prayed to be changed, etc.) become a couple and engage in sexual relations for the pleasure of it and the oneness and companionship and intimacy and love it engenders and enhances between them so they become more giving and fulfilled human beings?
4. Is it because of a reason I haven't listed? If so, what is that reason?

I am not a philosopher or logician or rhetorician, so I do not pretend to have presented all the necessary and relevant questions for addressing the topic. However, the ones I have posed are those that I would want a person who is promulgating or defending a position to answer.