Sinful acts always have concequences. You end up either hurting others or yourself or both. A sin is simply an act that is contrary to God or His will.
If you read the first chapter of Romans you will see all the different types of sins that man has engaged in, including homosexuality. In fact in the old testament, this is called an abomination (i.e. a very bad sin). God doesn't place different levels of degrees on sins, to Him a sin is a sin period. But he does with homosexuality, I think because it leads to so many other sins (i.e. in Romans). It also denies the natural use of a man / woman, thereby denying God's wonderful creation. Of course, if everyone engaged in homosexuality there would be no procreation of our species either.
But sin also always leads to sickness, illness, and disease. In fact, sickness, illness and disease come from sin or a sinful nature, they do not come from God. Thankfully, when Jesus Christ gave up his life for us he nailed every sickness, illness and disease to the cross with him (Col 2:14). That was the purpose of why he had to go through all the torture - he carried the sins of the world on him and nailed them to the cross. Meaning he defeated them because he did not remain dead, he was resurrected from the dead and he ascended to the heavenlies unto eternal life. So he defeated death for us. He also defeated sickness, illness and disease, so that when you are born again, one of the manifestations of the Holy Spirit is gifts of healing (I Cor 12). It is therefore available to now be healed of any sickness, illness and disease as part of the gift of Holy Spirit.