I agree with you completely. However maybe you should do some research for your RE class about different biblical interpretations that state homosexuality is OK.
There are only about seven passages that Christians use to justify why homosexuality is a sin. However, there are many arguments against them.
Firstly, I will point out Leviticus 18:22-24 ( http://www.biblegateway.com/passage/?search=Leviticus%2018:22-24%20&version=NIV ) and Leviticus 20:13 ( http://www.biblegateway.com/passage/?search=Leviticus%2020:13&version=NIV )
These are part of the Jewish law. I suggest you take a look at Leviticus 19:19 if you want to take them literally (http://www.biblegateway.com/passage/?search=Leviticus%2019:19&version=NLT ). This law does not apply to Christians.
These Christians also use the story of Sodom to justify why it is wrong. Yet it makes no sense. Take a look at Genesis 19:4-5 ( http://www.biblegateway.com/passage/?search=genesis%2019:4-5&version=NLT ). The act of raping the men (which is what the men were going to do) is different to a loving and caring relationship. So God destroyed Sodom because of rape and not homosexuality. Now take a look at Jude 1:7. ( http://www.biblegateway.com/passage/?search=Jude%201:7&version=WE )
Then when you look at Romans 1:27-32 ( http://www.biblegateway.com/passage/?search=Romans%201:26-32&version=NLT ). You see, this describes someone who is against God. It says “Their lives became full of every kind of wickedness, sin, greed, hate, envy, murder, quarreling, deception, malicious behavior, and gossip”. In what way is this describing any gay or Lesbian person who is seeking Jesus?
The translation of 1 Timothy 1:9-11 changed between the NIV in 1984 and 2011. (1984- http://www.biblegateway.com/passage/?search=1%20Timothy%201:9-11&version=NIV1984 ) (2011- This is because of a word called "arsenokoitai". It has been understood to mean paedophile or male prostitute. Again this has no similarities between a loving and caring homosexual relationship.
When you look at 1 Corinthians 6:9-10 the same thing applies. Look at the New International Version.