Personally, I think if you have hesitations about it, don't do it. Raise the kitties and find them homes. If this is something that will make you feel guilty and haunt you for the rest of your life don't do it; if not then do what you feel is best.
In my opinion, feeding the kitties off is better than having feral cats running around reproducing and being menaces. They'll just end up living short, harsh lives anyways. Your parents should be more sensitive to this issue, seeing that they care enough about their animals to get them spayed/neutered. How can anyone consider 'dumping' an animal to be a viable option? How can they live with themselves?? Some people just don't seem 'human' anymore.
( P.S. A cat abortion is just a spay with fetuses inside the uterus).