As a child, I was taught that sin exists in the mind; having a sinful thought was just the same as committing a sinful act. The Catholic Church says that contraception is a sin, except for the rhythm method.
The purpose of the latter is to consciously plan and act to avoid conception. This is called contraception. Yet, this is A-OK with the almighty. If logic were to prevail, all types of contraception, including the rhythm method, would be equally sinful.
Of course, logic has no place in religion. If men ovulated and had babies there would be no debate on these matters. You can imagine the rest.