I guess sex can be considered a human right in a certain way: no third party should be able to stop a consenting group of people to having sex.
While this is the wrong definition: another person should have sex with me. This latter definition often seems to be the taken meaning of "sex is a human right" and seems to be interpreted that way to advance the interest of that particular person saying it.
I was quite taken aback by the "Does that logic work for Blacks for instance ?" that started this above but then thought that instead of getting angry why not attempt to get my argumentation straightened out instead :).
As you say, that way of thinking makes women literally into less than even a service: for a service you at least need to pay for; a human right on the other hand (right to live, express yourself, freedom of speech etc) is normatively free. The fact that these women who somehow must sleep with you have rights too doesn't seem to occur to these people at all..