Well, regardless if it is or isn’t right for children to be instructed about sex is nearly irrelevant in this matter since they hear it every where else. They are learning it from music, the radio, television, movies, sadly even from parents, and definately among their peers. So they’re going to hear about sex either way at that age, I had definately already been introduced to that topic by 6th grade. The sad thing is that as Christians, we need to inform others of the what is and what isn’t okay.
If I was in your situation, and they “wanted” to talk about it, then I guess I would. Because even if you don’t tell them, they’ll get it else where. I would say simply, that first of all, that sex is a gift from God given to those who are married. Also, a priest once told me that the gift of sex is directly linked to children, and should not be seperated. Thus, it is not right that once you are married you should prevent children. The difference between NFP and all other birth control methods is as such, and I will try to explain the best I can.
When I got married, I had to explain this to my husband. God gave us free will, and thus we can decide whether or not we will let God do his will in this part of our life. As Catholics, it is our obligation to live “for God” and not for ourselves. By choosing to use condoms, pills, etc. we are telling God we don’t want his intervention until “we feel it is right”. We are choosing our way rather than God’s way. When using Natural Family Planning (NFP), we are using the natural cycle of a woman as birth control. God gave us a fertle and infertile time for a reason. The difference is, if God wanted to intervene, during the gift of sex, we aren’t preventing anything. God will not intervene when it comes to our free will, he created us to be free and to live as we want. It is our choice, as Catholics, to give that up and live by him, thus using a method that allows him to be a part in our life and to give life when he so chooses. Does this make sense at all?
NFP is 99% effective, just as effective as condoms and pills. You simply can’t have sex for around 7 days a month, during your fertile time.