QUOTE
Sexual activity most certainly is a conscious decision.
Blackstone,
I don't think so. Sexual activity will manifest itself in some form or another, regardless of conscious intent. On the other hand, without a good amount of training, religious activity won't manifest itself other than through the fundamental questions from childhood:
Who am I? Where did I come from? Why am I here? And sometimes, where am I going?
These questions have been answered by religious means for a long time; however, since the Age of Reason, these questions are also being answered by means of science. This shows that religious activity is not as much an inherent human drive as sexual activity is.
We know through science that the sex drive is regulated by hormones. Do we know the same thing about religious drive? I don't think so. There's no "Get Thee Religion" hormone.
Let's put it into another form: You don't have to teach teenagers to want sex. You do have to do this regarding religion, and starting at a pretty young age at that. It's called religious training.
We really don't have any sexual training to speak of. Don't do it, and if you do, be careful. That's about it.
Another contrast: Trying to not have sex is a discipline. Trying to not have religion is easy, even fun!.
Reversed: Trying to have sex is fun! Trying to have religion is a discipline.
And finally, no cult has ever had to brainwash people into having sex. Brainwashing is a necessary step to get cult followers to obey, even to the point of mass suicide/murder.
I think it's safe to conclude that sex is basic nature, while religion is not. All mammals have sex. Not all mammals have religion.