This article in the CCC about conscience is greatly mistaken
CCC 1800 which mistakenly says “A human being must always obey the certain judgment of his conscience.” This is a declarative, absolutist statement of the primacy of conscience using the terms “must” and “always” indicating no matter what. CCC1800 and 1790 are not Catholic teaching. They are in grievous error evidenced by the fact that they have no footnotes, no references, no documentation whatsoever. They are not found in any Magisterial document whatsoever. Following is the real Catholic teaching from two Papal Encyclicals and the Council of Trent that decisively condemn following conscience into intrinsic evil i.e. abortion/murder etc.
“The negative precepts of the natural law are universally valid. They oblige each and every individual, always and in every circumstance. It is a matter of prohibitions which forbid a given action semper et pro semper, without exception, because the choice of this kind of behaviour is in no case compatible with the goodness of the will of the acting person, with his vocation to life with God and to communion with his neighbour. It is prohibited — to everyone and in every case — to violate these precepts. They oblige everyone, regardless of the cost, never to offend in anyone, beginning with oneself, the personal dignity common to all.” VERITATIS SPLENDOR, 52
“But no one, how much soever justified, ought to think himself exempt from the observance of the commandments." Council of Trent, Session 6, Chapter XI, page 38
"Before the moral norm which prohibits the direct taking of the life of an innocent human being "there are no privileges or exceptions for anyone”. Evangelium Vitae, 57
“The negative precepts of the natural law are universally valid. They oblige each and every individual, always and in every circumstance. It is a matter of prohibitions which forbid a given action semper et pro semper, without exception, because the choice of this kind of behaviour is in no case compatible with the goodness of the will of the acting person, with his vocation to life with God and to communion with his neighbour. It is prohibited — to everyone and in every case — to violate these precepts. They oblige everyone, regardless of the cost, never to offend in anyone, beginning with oneself, the personal dignity common to all.” VERITATIS SPLENDOR, 52
“But no one, how much soever justified, ought to think himself exempt from the observance of the commandments." Council of Trent, Session 6, Chapter XI, page 38
"Before the moral norm which prohibits the direct taking of the life of an innocent human being "there are no privileges or exceptions for anyone”. Evangelium Vitae, 57