Comparing two or more things

What are you comparing? There are a few mistakes in the sentence, here is the correct way to write it: 

Stefanson stated that embalming is an open choice for the family, but other people want their bodies to be treated more naturally after death, without the use of chemicals. 

Also, it's unclear whether Stefanson stated 

embalming is an open choice of the family

or

embalming is an open choice of the family but other people wants their bodies to treated more naturally after death without the use of chemical.

I agree with Alex (note also his inclusion of a comma).

I would also ask, what do you mean by "an open choice of the family"? I suspect, from the context, that you mean the choice is available to the family. If so, I would change the wording slightly (I'm working from Alex's amended version): 

Stefanson stated that embalming is a choice open to the family, but some people want their bodies to be treated more naturally after death, without the use of chemicals.

The ambiguity around what exactly Stefanson said remains and should, ideally, be addressed.