Using birth control shuts God out of that process. This means birth control is inherently wrong.
I firmly believe that sex should be between a man and woman within marriage. I also believe God "opens and closes the womb". Conception of a baby is indeed a miraclulous happening and the part each partner plays in this event should be respected and accepted for the blessing and gift from God each child represents.
But...I also believe God let us in on the "secret" about how this miraculous event happens and how to have some control over it as well. Parents should also be responsible and be able to provide for their children. I personally know people that became pregnant even while using the pill, condoms (not all that reliable, I know), rythmn method (old NFP ideas), NFP and even vascectomy! The "unplanned" children resulting from these were and are accepted and loved. Unwanted pregnancy does not mean unwanted child - or shouldn't.
So, back to the subject... if NFP can be used by a couple who would like to try not to have a child, in other words enjoy the intimacy and pleasure of the marriage bed without intentionally trying to conceive, why should the "method" they use be so important? Again, I do not condone any method of BC that destroys the human life that may be conceived. It understandably appears like the "church" is sticking its nose into a quite personal decision that should be between a couple and God.
Natural Family Planning means, for that time that the woman is fertile, the couple do not have sex.
The woman takes her temperature every day and charts it. She also notes bodily changes. Over time, she can begin to see a pattern and knows the signs of fertility. When those signs begin, she and her husband do not have intercourse.
To refrain is not sinful; to deliberately engage in the pleasure of sex without allowing God’s will to be part of the process is the sinful part.
Also, it gets more terrible than that because the pill and other forms of contraception are actually allowing you to conceive but flushing the embryo out of your system. So people who use those forms of contraception are actually, usually without knowing it, repeatedly aborting their babies.
The Church will never condone this aptly named “birth control.” It is not conception control. It’s genocide.