Birth control doesn't always work... so what the hell has that to do with anything? Most times for most women it does.
Conception is nothing but the act of becoming pregnant. What definition is there to change, unless of course you're trying to confuse yourself in the way you are.
Until a fertilized egg implants in the right place, a woman isn't pregnant. Many times the egg doesn't naturally implant when fertilized, so just how the hell is she then at all pregnant in any real sense.
The contraceptive pill whether progesterone only or the ordinary pill, is to stop the egg being released in the first place. To delay release so sperm doesn't work making it difficult to get to the egg. Also makes the lining of the womb thinner and less receptive to an egg.
It stops the process to pregnancy.
Debate with you ?... what a joke. You haven't a clue. All you do is scream troll every two minutes and have no idea what you're talking about or spell it properly.
You run off to your outdated religious bullshit websites, copy what they say without critically considering it , then parrot it in ET. It's not debating, just debunking your ignorant and senseless bullshit claims.
If you don't like contraceptives don't use them. Millions upon millions do and want to use them. Keep your archaic primitive superstitious beliefs out of it.