Opinions about my 16 year old

I'm not a parent, but my mom would have said "no" with no exclusions when I was 16 years old if it helps.

How old is the girlfriend? 

I'm not a parent either, but if she's over 15 and your son is 16 then I don't see the problem by letting him sleep over. If she's over 15 they're aloud to have sex and not letting them sleep (not sexually) together is cruel in my opinion. They're old enough to sleep together if they're, by law, is old enough to have sex. 

Since sex is legal from 15 years, I think most parents allow their 16-year-olds to spend the night with their boy-/girlfriend. Our daughters have had boyfriends here over night from 15 years, and so have most of their friends.

She is 15. 

I was raised that moral and legal are two separate issues´, but I am torn because it seems as though sweden raises very well rounded adults

My parents said no to sleepovers when I was 16. But I pointed out that if we wanted to have sex we could do it whenever not only by night... Perhaps, rather than forbidding him to sleep over at his girlfriend's you could tell him your concerns? Maybe he (like me at his age) has no plans to do more than just sleep?

My son is sexually active with his girlfriend, he has talked to me about it.  Although I accept it, I don't want to promote it.  It's like saying, well if you are ´going to drink anyway, you might as well do ir here.  Although our kids will always do things that the parents are not comfortable with,  I feel they still need guidelines to follow

May I ask why you won't let him sleep over at hers or vice versa? If you already know they're sexually active, what's the big roblem really? 

Don't get me as grumpy, I'm just curious.