In a National Catholic Register column, Mark Shea quotes a number of people who have neither children nor impeccable reading skills. Among the quotations is this [links added]:
I'm a childfree Catholic but I believe in global warming, I believe in birth control, AND I think the writer of this article is an ignorant nut job. Not all Catholics are brainwashed sheep. We ARE allowed to form our own consciences.
Setting aside the self-aggrandizement (of a sort so common we no longer notice how odd it is) of the first two sentences, I want to look more closely at the last one:
We ARE allowed to form our own consciences.
I'm not a big fan of that "allowed." It's not clear whether it's the Church or her Founder granting the allowance, though either way the context suggests the Church isn't enthusiastic about it. Which is ironic, intentionally or not, since what the Church actually teaches is, "Everyone must avail himself of the means to form his conscience." Forming our own conscience isn't merely "allowed," it's required.
What is not allowed -- I repeat that word for rhetorical effect, but it's an otherwise lazy choice; this isn't a matter of the Church forbidding something, it's a matter of the Church pointing out that the thing is wrong to do; the former is a matter of governance, the latter of doctrine -- is to form our own consciences along lines contrary to Church doctrine. It's wrong because it guarantees an ill-formed conscience. It's also foolish, because one of the reasons we need to form our consciences is because concupiscence makes us unlikely to live according to Church doctrine:
The education of conscience is indispensable for human beings who are subjected to negative influences and tempted by sin to prefer their own judgment and to reject authoritative teachings. [CCC 1783]
Someone who "believe[s] in birth control" -- and how's that for a revealing expression? -- does not believe in conscience formation as taught by the Catholic Church.