The etymology of the word is also somewhat telling.

at one point in time there was little distiction between.  'the right due a person' and 'you are right to seek ways not to sin'.

So it is easily concluded that it is wrong not to give one his 'right'.

because the two are opposite terms with slowly deviating definitions extending from the use of the phrase 'right custom'.  'right custom due'

'right due too <x>'. 

Given that Perhapse the best definition of the term 'right' in the sense of 'human rights' would be

right: the correct way of acting towards an entitity as dictiated by both social norms as well as devine and natural law.

Further it would seem to me that from the materalistic perspecitive there can be no such thing as a inalianable 'right' including 'human rights' because for there to be such implies the existance of a 'natural law' which cannot exist without the existance of a natural law giver.

"Right" obviously has different meanings as function of context.  As a philosopher, I can tell u something of "right's"  dizzinging history varied contextualized meanings.

 A right scientific hypotheisis accurately predicts outcomes; a right mathematical equation proves the theorem ( there are, of course, many other types of mathematical right, Fishman); right in a juridcal context refers to a judge's conformity to case law hisitory in its decision; a right moral act or attitude refers to conformity to a given pre- established canon of '"right and wrong" in which a person acting thus and so is said to be morally right; right can refer to eternal and absolute truths that are said to precede human existence and time/ space as in "certain inalienable rights" given by God, or the right to life and dignity inherent in the human being because conferred by God; others invoke these same invariant rights of life and dignity on a humanistic ethic; if u are a Southerner, right can mean "very" as in " This chicken is right good!."

In general, right is a rather tautalogical word for in all instances I can think of, it at least means something of the form "..and this act, speech, attitude, or whatever conforms to what we think of as right... where "conforms to" can mean varied things : conforms to correct thereom proof; conforms to the way we here in the mountains should act and feel about things; conforms to eternal truth; conforms to what is essential about human morality; conforms to correct experimentation; conforms to logic; conforms to Catholic teaching, to the Buddha, or to the Reformers...  

So it seems there are two types of rights those that come from what we invariably are ( for instance human rights) and those that come from our state ( for instance my boss may have certain things 'obedience' for example due him that I do not.) .

For me all this rights stuff come from Thomas Paine's Rights of Man and the Declaration of Independence and Our Constitution.  But, that is jsut me, the silly American pig-dog.

In your context you mentioned:

"So I think I understand what basis Catholics come from when they talk about rights, I do not understand what basis one can have for discussing such a thing as a ‘universal right’ outside of a religion context."

This has to do with the inherant value of human beings.  I guess it must be assumed that there are more than one or that for us to have rights we must be a community of people.  Rights would have no value if each man was an island and didn't give a rat's hind-end about what others felt were rights.

Also, in order to define it as a right or a "given" we must agree upon it.  It must be something we all take for granted.  In short it should be based on common experience of people.

Yet it is something we own inside our own subjective realities.

A right is something that:

1. Community (Social).

2. Based on common experience.

3. Something we all take for granted.

Seems like we are working toward a way to communicate and get along so that we can get beyond the basics toward common goals and a common and better future.

GK - God is good!

Thomas Paine - also wrote in 'common sense' that we should throw off the dictates of the king for the same reason we through off the dictates of the pope!!.

I'm not so sure I trust his social theory.

However he certainly assumes the existance of diety.

Which is one of the things I consider so dangerous about those who make the claim:" I don't believe in imposing my religious convictions on others ..". 

Given that a good law is one that conforms to laws of God and a bad law is one that does not I don't see any way of determing what is good or bad law other then religious conviction. 

It seems to me the compromise of American system is one that lets people of many different beliefs fight it out on the political spectrum without bloodshed.  ( this is a really great thing IMHO) It lets what they hold in common to be right to be truely right and the majority rules.

 However, to say:  "I don't believe in imposing my religious convictions on others ..".  is to undermine the whole thing because it creates the illusion that there is some other source from which a law can be drawn. 

In the end all laws reflect someones morality.