extending the meaning of birth control

I recently saw the new film Angels and Demons at the movie theatre, and it has me thinking about all of these issues that I have with the Catholic church. Well, I guess one of my biggest ones happens to be their stance on birth control. And if you couple that with an odd conversation at Tulsa Studies you will sort of get the idea for this post. Hall announced to me that she and her husband discovered an interesting fact about Oklahoma -- that is has the highest rate of ED. Well, this got me thinking about sex and birth control and then the Catholics. And of course with this issue, a double standard presented itself in my mind because of recent cultural developments of the past decade.

With the advent of Viagra in the 1998, men with erectile dysfunction are able to have sex. If the end result of sex according to the Church is to conceive, then couldn't Viagra be seen as a form of birth control? It is altering the potential outcome of a heterosexual couple's chance of having a baby. "Pfizer, leaving nothing to chance, has even requested and received the Vatican's unofficial blessing for Viagra (according to this article in TIME)." I just think this is interesting because the Vatican condemns IVF and stem cell research. According to this article at Catholic Insight, "IVF violates the rights of the child: it deprives him of his filial relationship with his parental origins and can hinder the maturing of his personality. It objectively deprives conjugal fruitfulness of its unity and integrity, it brings about and manifests a rupture between genetic parenthood, gestational parenthood, and responsibility for upbringing. This threat to the unity and stability of the family is a source of dissension, disorder, and injustice in the whole of social life." (Notice the gender at work here, too. Deprives "him" of "his" rights.)

While Viagra is not producing the same consequences that IVF apparently creates, it does in a way manifest a "rupture" in that without Viagra it would be difficult for the man to ejaculate. Or at least that is how my simple understanding of ED works. Any thoughts?