The way I see it, any sin can be forgiven, accept rejecting jesus christ all together. So, although it is a sin, it doesn't mean it will condemn them right away. I'm sure if they are a good person and do good deeds and believe in christ, they will be allowed into heaven. That doesn't mean they won't be judged.
Unforgivable Sin
As hammer put it, accept jesus truly and faithfully, and you shall be forgiven for all sins.
*This is based on a specific religion here. It all comes down to your belief after all. It's not like we can prove that christianity is right or anything.
*The question to this thread has been answered, it is a sin. So I guess this is a, "can they get in heaven" thread. So, try and add to that and answer the original one if you like.