This is worth dragging out of a combox.
A reader objects to the Catholic position against contraception as an intrinsic evil by saying,
If so then all the celibate monks and priesthood are an expression of this intrinsic evil as any move to positively reject that can be seen as an offence against God.
Celibacy is no more contraceptive than holding your breath or being a carpenter. Masturbation, on the other hand, is contraception with two hands; the pill is but masturbation with four hands. Contraception is the prevention or perversion of the intrinsic telos of any coital/connubial act. Celibacy is not a connubial, much less coital, act and is therefore not contraceptive. Celibacy allows for the full expression and enjoyment of all the moral-spiritual goods/gifts of each sexual act a celibate person enters into: which is to say none. You may as well charge a fasting Christian with bulimia; both accusations are equally absurd. Fasting respects the nutritive value of every bit of food — none — whereas bulimia rejects and quite literally rverses the telos and benefit of eating. Contraception is sexual bulimia (or maybr the reverse is the greater truth).
Also, to head you off at the pass, reader, neither is NFP contraceptive, since it allows for the full fecund potential of each and every coital act. It merely respects the fact that God has implanted seasons of in- or semi-fertility in women. NFP is 100% potentially procreative, (or, if I may neologize, “procreatable”), even if it is not always actually procreative. Contraception, by contrast, violates all the fecund potential and therefore defies the created order of God. NFP allows a man to give himself FULLY — fertility and all — to his wife, while contraception short limits the total self-giving that sex is meant to be.
I refer you to my own thoughts on these matters, if you really want a more rigorous explanation.