The 90(!) comments on my post on the difference between being Green and being a Christian who cares about the environment (here) have ended up being a long conversation about different attitudes to contraception.
Chris G-Z takes a traditionalist Roman Catholic perspective on the subject, and I have been puzzled on the justifications being offered. In particular, in situations where a married couple come to know that they are not fertile, we pursued the question of whether it was legitimate for sexual relations to take place. Chris agreed that, in such a case, it was licit "to have sexual intercourse for non-procreative purposes, so long as, if it is procreative, then the conception is allowed to take its natural course" and so long as the sexual relation is "between a husband and wife married to each other".
I am baffled as to the difference between this and accepting the use of contraception. I'm not aware of a contraceptive method with 100% reliability, and I'm aware of a number of people (myself included) who, should contraception fail, would be willing to accept the consequences of that failure (eg raise the resulting child). There seems to be an acceptance that sexual relations are not exclusively for purposes of reproduction, which I think is right, but which runs against the grain of the teaching on contraception.
I should add that I think this is a problem with the official teaching of the Roman Catholic church, not with Chris' logic generally. It may be that there is something in the official teaching which we haven't unearthed yet.