Firstly, I must say I totally agree with Ultima Ratio, the original post was made in good faith, and not questioning the authority of the Catholic Church, and so our replies should also bear witness to that, otherwise they are not answering the question, but just diverge us from the real issue at hand.
Here is my response:
It is true that the Nicene-Constantinople (Nicene for short) Creed cannot be “updated” since it would no longer be the creed that was arrived at by the Councils of Nicea & Constantinople (hence Nicene Creed for short), but it is also true that the church could use any other creed if it so desired, including a more up-to-date one. As previously stated, The Church created the Creed, not the other way around, so can create new versions whenever it is necessary. However, the CCC (Catechism of the Cath. Church) also tells us that no accepted creed is ever later wrong, or superceded by another, but is just another expression of the same faith, that may be more or less relevant at a particular time, or have a more fuller developed theolgy. It is note worthy that the CCC mentions also the: Apostle’s Creed, and the Creed of St.Athenatius, and does so in such a way as to show that not one of these creeds is “higher” than any other, but all are equal.
Pope Paul VI in 1968 came up with a modern creed. This was widely published at the time, and can be found at the following link:
ewtn.com/library/papaldoc/p6credo.htm
This creed it is not used during the Mass since:
the Catholic Church seeks to call all separated Christians to full unity, and so uses this common creed during Mass (it wasn’t actually inserted officially into the Mass of the Roman Rite until many centuries after the council of Nicene);
The Catholic Church also believes in continuity. The recitation of the Nicene creed at Mass, also reminds catholics of the ancient unchanging nature of our faith.
However, the church could use a different creed at Mass if it decided to.
**As a final note, it must be said that items such as abortion etc. are moral issues, as opposed to purely faith beliefs. **Traditionally, such moral matters are never put into creeds, but perhaps now is the time to do so.