Anyone know what
 

'unnatural affection' is, that is quoted in the bible?

Yes.

If we define "natural" as "that which occurs most frequently outside of civilization," then strict heterosexuality is fairly unnatural. I'll assume by "natural" they mean "what I'm most used to or comfortable with."

Animals, guys and ugly women.

I hope one of our Greek scholars will weigh in, but translations I've consulted cast doubt on the idea that the passage refers to homosexuality. For comparision:

2 Tim. 3:3

NRSV: 3 inhuman, implacable, slanderers, profligates, brutes, haters of good,

ESV: 3 heartless, unappeasable, slanderous, without self-control, brutal, not loving good,

GNT: 3 they will be unkind, merciless, slanderers, violent, and fierce; they will hate the good;

NASB: 3 unloving, irreconcilable, malicious gossips, without self-control, brutal, haters of good,

NIV: 3 without love, unforgiving, slanderous, without self-control, brutal, not lovers of the good,

KJV: Without natural affection, trucebreakers, false accusers, incontinent, fierce, despisers of those that are good,

ἄστοργοι (without natural affection) refers to the lack of affection (στοργή) that occurs naturally (duh), usually between parents and children. Rarely sexual love. So the LSJ Greek Lexicon.

We would probably say "heartless" or "cruel."

That seems pretty clear
 

these days.........just open up the newspapers on a daily basis.

Thanks, Solon.

I don't think that's the answer Exie was looking for.

SIEQ and Solon, thanks. Good stuff.