Do Christian groups which think homosexuality is a sin think you can be a practicing homosexual and also a Christian? Many Christian groups condemn homosexuality as a sin, pointing to specific passages in the Bible and traditional Christian views on sexuality and marriage. 

How do these groups handle the question of whether a person can be both a practicing homosexual and also a Christian? 

Are there any additional steps required? Do these groups teach that it would be sinful to continue practicing after one became a Christian?
1. What you "are" is irrelevant

Let us first distinguish between being a member of a class - in this case homosexuals - and engaging in any sort of behavior.  For many people, being a member of the class "homosexual" means having feelings in one direction or another.  In no event would a "temptation" towards a certain behavior be taken as exclusion.

James makes it clear that temptation itself is not sin.

Galatians also makes it clear that being a member of any class is irrelevant:


  26 So in Christ Jesus you are all children of God through faith, 27 for all of you who were baptized into Christ have clothed yourselves with Christ. 28 There is neither Jew nor Gentile, neither slave nor free, nor is there male and female, for you are all one in Christ Jesus. 29 If you belong to Christ, then you are Abraham’s seed, and heirs according to the promise. 


At the risk of self promotion, look at this answer for more.

2. What you do is irrelevant

Even without broaching the question of whether or not homosexual activity is sin, this question still be categorically answered "Of Course you can!"  

The primary message of the Gospel is grace.  Grace is God's unmerited favor - the free gift that he bestows in which he says "You are forgiven"

Remember that before God ALL MEN ARE SINNERS.  As Isaiah 64:2 says, eve "our righteousness is as filthy rags" in God's sight.  There is simply no person that God loves more than any other - he is "no respecter of persons"

Furthermore, as Ephesians 2:8-9 states, 


  "For by grace you are saved through faith - it is NOT through any work of your own, lest any man should boast."
  Since there is nothing that you do to earn your salvation, your status is irrelevant.


3. Whether or not you continue in homosexuality is the only question

Once one is a Christian, one is expected to grow in Christ - to become more Christ-like. Here is where as you mature, you may want to put these things away.  But, understand, obedience comes out of love and desire to be more like Christ.

As Jesus says in John 14:12 "If you love me, keep my commandments."  It is explicitly not "Do what I say so that I will love you."

Under no circumstances should one believe they need to get clean before being washed by Jesus!

Finally, what you probably want to ask is "Is Homosexuality a Sin"
This question has been asked here and here.  Gene Robinson, the Episcopalian bishop of New Hampshire who left his wife for another man likes to argue Acts 10 - (Let no man declare unclean what God has declared clean) - that God is doing a new thing.  I personally don't think God's word has changed on that matter - but I bring it up to say that Christians debate the matter. 

In any case, sin is irrelevant.  God's grace is what is important.

Of course you can be whatever you want and be a Christian.  The question is whether or not God will leave you that way.