More on Catholic teaching about matters sexual . . .
Many wonder, where does the Church's teaching on these matters come from? They challenge the Church's credibility on the matter. Sometimes (here comes more silly thinking) the argument comes down to the calendar: "How can the Church make her teachings understood in this contemporary age" (or similar language) -- as if 21st century Man is a radically different creature, sexually, from all that went before! All we can take credit for is finding new ways to do what human beings have always wanted to do: have their cake and eat it, too.
Now, let me propose thinking about the matter this way--just for kicks, let's take out all supernatural references, all theology, all Sacred Scripture, all "churchy" stuff. And just think about this by looking at the matter itself. What can we discover about sex simply by looking at it?
We might ask--is there any purpose or meaning to it? If so, what?
Well, we find that answer quickly enough, don't we? We know what sex does and is "for": it's about reproducing the species; and we discover it is also about bonding two people together.
We also discover, fairly quickly, that not all people who have sex, produce children -- or, for that matter, get very bonded. (This is where the question of homosexuality often comes into the discussion: why, look! Some people are oriented toward their same sex! Therefore, all conclusions are suspect!) We also discover that some people have eyes that do not see; that hardly discredits the conclusion about what the eye is for.
So--we know what sex is for. We quibble about it, when the conclusion is unhelpful to what we want.
Now, as to monogomy and fidelity. It seems clear that men especially like to have lots of sex. I'm not an expert in matters Darwinistic, but I think one argument is that this makes sense from the point of view of evolutionary theory. However, the female doesn't care all that much about theory -- she cares about the child the man fathered, and expects the man to stick around. It doesn't take too long for humanity to figure out the benefits of this, and so the customs and laws that demand it are pretty common-sensical. (And even if the new mother doesn't care, the larger community does, and will help her to care.)
My point is, you don't need to thump a Bible to justify heterosexuality as the norm, and for fidelity and exclusivity in sexual unions (marriage), and for society to care about such things.
Indeed, if you really did take the Bible, and religion out of it, I think those who argue specifically for social and moral indifference to homosexual behavior, and for autonomy in sexual matters generally, would find the climate far more hostile than they think it is because of a Biblical/Christian milieu.
Well, for one, if I assert, "I have a right to ____," the reasonable question is, "who says?" A Christian, or a theist, would say, "God says." Without God, who says? Well, then, I say. Fine--who are you?
The inevitable result, it seems to me, is that rights have to arise either from the exercise of power, and social agreement. Because while I can assert whatever rights I like, vindicating them all on my own isn't a very promising approach. Trying to vindicate a right the rest of society doesn't think much of is even less promising. Hence, I need to get society to agree with me about what rights I claim. (And even if I say, "God says so," I still have to do this, unless we all agree on some mechanism of determining that God said it--such as consulting a text, or teaching authority, etc.)
So when we hear assertions of "rights" in relation to sexual "freedom," who can marry, marriage/divorce/remarriage, sex "behind closed doors," etc. -- the question remains: "who says"?
Furthermore, there is no question that society reasonably is concerned with all these matters. Through most human history, societies have been very concerned about reproducing more children. We've experienced a period, very brief in human history, in which society has emphasized having fewer -- and already, governments and others are saying, "uh oh..." So it's not terribly hard to figure out why a society might care whether men get together with other men, vs. with women. And without a higher authority, such as God, to appeal to for some fundamental rights, it isn't terribly hard to imagine a society that doesn't give a hoot about sexual minorities saying, "but I have rights!"
Ah, well, there is more I might say, but let this be food for thought, as I go meet a friend for dinner.