Sorry for the delayed response. There is actually a direct link between the legitimized use of contraception and the attempts to legitimize “same sex marriage.”
Contraception is nothing new. Ancients used lamb intestines for condoms and herbalists had concoctions that may actually have suppressed fertility (like today’s pill) and/or caused early abortions. The historical record contains plentiful example of Early Fathers condemning the use of these attempts at contraception. These early fathers may not have had the scientific understanding about conception that we do today, but they DID have something we mostly today severely lack: a combination of observation skills and the ability to recognize cause and effect through reflection and pondering (no TV and iPods!). They clearly saw that it was GOD who made sex and babies linked. They also clearly saw that when man attempted to delink them through contraception, sex became degraded in the process.
It IS subtle, because GOD didn’t make sex ALWAYS lead to children. The key is that when WE try to take action to sterilize a sex act that GOD would have made fertile, we actually change that act into something at least partially degrading to both spouses. This damage doesn’t (necessarily) occur if the couple refrains from sex on those days God made fertile when they have a legitimate need to not get pregnant at that time.
This is also why the Catholic Church opposes technological conception methods like IVF (even if you remove all the abortive abuses). A child has the right to be the result of the loving coupling between his father and mother, not the outcome of a neato lab experiment. It is a subtle act of violence against the child to take that right away from him. This is a hard thing for infertile parents to hear because we today have come to believe that parenthood is our RIGHT. It is not. It is a gift given by God, and sometimes He choses (in his mysterious and hard wisdom) to give a different gift.
We don’t necessarily oppose fertility drugs to help a woman who doesn’t naturally ovulate. It IS the proper role of medicine to help fix malfunctions that occur in the human body. If it can help her ovulate, then the couple can conceive as God intended. See the difference?
What does all this have to do with “gay marriage?” Well when protestantism embraced contraception, they took a Trojan Horse into the city (no pun intended!). Inside this horse lurked a nasty enemy: a subtle change in attitude towards marriage that made it all about the two lovers, not the whole resulting family. Once this attitude became fully entrenched, gay marriage was inevitable! If marriage is primarily just about the union of two lovers, how can you deny it to two lovers because they have inner attractions that they didn’t chose to have that are different than yours? That’s a LOT harder temptation to resist than when marriage was defined as the loving union between man and wife that forms the foundation of the family, which in turn forms the foundation of civilization itself! Sad to say, but it is logically inconsistant to embrace contraception and reject gay marriage. If protestantism holds out against the cultural tide, I predict it will only be for the wrong reasons: it’s easier to oppose a sin one isn’t personally inclined towards! That doesn’t bode well for our witness to the world.
Consider the historic christian position on contraception (inherently evil). Read Christopher West’s “Good News About Sex & Marriage” for an easy reading introduction. Christendom would be a lot more believable to the world if we lived the hard teachings that were hard on US in addition to those that are hard on THEM.