It's true your pet will never grow up and take care of you when you get old. In fact, you can count on the fact that you will outlive them, barring great misfortune on your part. Their lives are so brief, and they give so much, even if you don't always have time for them.
I recently lost my beloved cat Vladimir. He was with me for 19 years, spanning half my life, thus far. The better half I might add. I was careful who I told about my grief. I learned from a grief therapist that a new loss can open up all the old ones, and my mourning of this cat's passing ran pretty deep. It actually made me wonder if he didn't really fill the "missing child" niche for me. It made me doubt my choice, for a moment.
Cats and children really do not compare. Cats are way easier. I don't think it is a good idea to have children so they can take care of you when you get older, but I have to admit the possibility that they might is rather appealing. One of the nicest things a friend said to me was, "you are a such a positive, warm person Teri, you will always have people around who will help you."
That's a nice sentiment too. I am hanging on to that thought.
Now we're thinking about getting a dog. Hey, it's a big step for a CF couple.