At Ethical Views of Christian Denominations from ReligionFacts they categorize these issues as:

     Sexuality: Premarital sex, Adultery, Homosexual Behavior
      Marriage: Divorce, remarriage, same-sex marriage
        Gender: Women in Leadership, Gender roles in marriage
Life and Death: Abortion, Contraception, Euthanasia, Removal of life support, Suicide,

What the Bible says:
Levititicus "If a man has sexual relations with a man as one does with a woman, both of them have done what is detestable. They are to be put to death; their blood will be on their own heads."
18:22 and 20:13

Or do you not know that wrongdoers will not inherit the kingdom of God? Do not be deceived: Neither the sexually immoral nor idolaters nor adulterers nor men who have sex with men[a] 10 nor thieves nor the greedy nor drunkards nor slanderers nor swindlers will inherit the kingdom of God."
1 Corinthians 6:9-11

What Jesus Says:
"What comes out of a person is what defiles them. For it is from within, out of a person's heart, that evil thoughts come--sexual immorality, theft, murder, adultery, greed, malice, deceit, lewdness, envy, slander, arrogance and folly. All these evils come from inside and defile a person." [Mark 7:20-23 ]

Some Pharisees came to him to test him. They asked, "Is it lawful for a man to divorce his wife for any and every reason?"

"Haven't you read," he replied, "that at the beginning the Creator 'made them male and female,' and said, 'For this reason a man will leave his father and mother and be united to his wife, and the two will become one flesh'? So they are no longer two, but one flesh. Therefore what God has joined together, let no one separate." "Why then," they asked, "did Moses command that a man give his wife a certificate of divorce and send her away?"

Jesus replied, "Moses permitted you to divorce your wives because your hearts were hard. But it was not this way from the beginning. I tell you that anyone who divorces his wife, except for sexual immorality, and marries another woman commits adultery."
Matthew 19:1-9

Female leadership Women should remain silent in the churches. They are not allowed to speak, but must be in submission, as the law says. As in all the congregations of the saints, women should remain silent in the churches. They are not allowed to speak, but must be in submission, as the Law says. If they want to inquire about something, they should ask their own husbands at home; for it is disgraceful for a woman to speak in the church. [1Cor 14:33-35 ] A woman should learn in quietness and full submission. I do not permit a woman to teach or to have authority over a man; she must be silent. (NIV, 1 Timothy 2:11-12) See What Does the Bible Say About Women in Ministry? Homosexuality and Adultery:
Christ had a lot to say about adultery and next to nothing to say about homosexuality.

Christ had a lot to say about adultery and next to nothing to say about homosexuality.
See Christian Ethics Some people say that his reference to sexual immorality (the King James translation uses fornication here) in Mark 7:20 refers to homosexuality.

Paul says in 1 Corinthians 6:9 that homosexuality will keep you from entering the kingdom of God.

Adultery:
Matthew 19:9 says, "I tell you that anyone who divorces his wife, except for marital unfaithfulness, and marries another woman commits adultery."

What if you view these in terms of harm done? My personal ranking, bad to not so bad, is:

1. Adultery in terms of damage to families. (I'm referring to adultery which leads to divorce or severe marital discord.) *
2. Spousal abuse. It's hard to show that the Bible's relegation of women to second hand citizens (Several women played a prominent role in Jesus life so you can dispute this) leads to spousal abuse. That's like proving that pornography leads to rape. *

   Note: I am flipping the argument around, saying the Church's interpretation of the Bible is causing the problem and strong women are not the problem.

3. Homosexuality - If Homosexual marriage reduces the incidence of promiscuity in the gay community it could have some good.

* I suspect there are those who would make a case that if submission of wives, which occurs in several places in the Bible, was instilled in Christian women, then # 1 and 2 above would not be as likely to break up families. I don't know anyone who has.

I agree with the exclusion of homosexuals from ordination in mainline churhes because of their promotion of this lifestyle (e.g. Gay pride parades). Adulters may brag about their exploits while watching football with their male friends, but they don't make public displays of it.

Books:

links:
Standards for Church Leaders
Political Issues (Abortion, Homosexuality, Environment, Evolution, ...)
Gay Marriage
Comparison Chart of Ethical Views of Christian Denominations - ReligionFacts
Gay Marriage
Political Issues (Abortion, Homosexuality, Environment, Evolution, ...)
Rise of Women Pastors