Hygiene.

Let me elaborate on hosas comment, 5000 years ago after adam and eve were properly married and went to consumnate their marriage it was a good thing they were both heterosexual.

Hard to tell when it comes to fictional characters (as some see it). For all we know, Adam might have "been" with Eve just to procreate, while really he much preferred intercourse with, say, sheeps or pigs. Or maybe he was as gay as they get, just that he didn't have anyone to experiment with? All of humanity's sexual traits must have existed in Adam, as he was the very first male. So with that reasoning, he might as well have been with most things that move, as well as quite some immovable objects, if you look at the sexual diversity that exists today.

I don't remember the Bible being very specific about it.

I might very well be wrong though, has there been bible studies about it?

This comment is relevant how?

Is heterosexual intercourse clean and homosexual intercourse dirty? Afterall, in both cases, it can involve anal, and mouth contact to lower-body parts. So if it is that, it is merely a bigoted view which isn't respective of the facts.

What he said.

Bad style Azathoth.

Also very little relevance to the topic at hand.