Natural or Unnatural?

I guess almost every Indian should be familiar with this number by now. This number has been in the news for quite sometime now.

Its the article 377 of the Indian Penal Code, which "criminalises homosexuality" -- the news papers puts it. I was not thinking about writing something about it, until one of my colleague , stated the move to remove this law as

Indian Judiciary showed again today tat itz the dumbest in de earth ...

He replied to the arguments in that thread as

Its like eating stones when there is trays of chololates... Thats not natural and it results in nothing...
when kid does that we counsel it to chocolate...

So is having multiple spouses is also Ok???
stilll more etc., etc.,... Read More
All these have by mutual Consent !! but why tats are illegal...

I dont say tat they should be hanged... but shall have a different way of counselling them and understand...

Then its irrelevant to have a constitution and society if people are allowed to do watever they wish...

I don't agree with this. Not because I have something against anyone or supporting homosexuality.

Now prominent personalities from various religious backgrounds and walks of life are commenting for and against the legalisation of homosexuality. One of the most frequent arguments that I found out was the seeing homosexuality as "Unnatural". Thats one thing that I find confusing. What is it that makes things natural and unnatural?