But one does hear people claim that it's different when it's your own child; you might well feel differently yourself, in that particular circumstance.

I've never seen that as a good reason to have a child. What if it doesn't end up being different? If you have no reasons to believe that it would end up being different and you don't want children, then banking on that remote hope seems a bit overly idealistic to me.

Personally I learned recently that apparently my distaste for children was shared by both my mother and grandmother. Apparently (or so they claim) they did get over it enough once they had an unwanted pregnancy, but really! It still seems overly idealistic thinking to me.