I understand what you are saying, that you have bred before and are not an inexperienced breeder.  I also see what you are saying, that if the rescue is spayed, you obviously are not getting that dog to breed with.  Those parts I understand what you are saying.  If you want to breed your dog, it's your dog and your right to make that decision.  
 
Where you and I separate in thinking is I do not understand the pregnant woman/adoption correlation.  We are not euthanizing children in orphanages by the million a year due to homelessness and no funds to care for them.   
I understand your frustration.  Perhaps you could watch for an elderly person who needs to rehome a neutered animal and would welcome the home you would provide.  Sometimes pets are displaced due to illness or divorce who would appreciate a home.  I wish you luck in finding your little one a neutered companion.   
Just to get to know each other a little better, I have always had female dogs, and I have never felt the need to breed them.  I just could not trust someone else w a little one I helped bring into this world.  I couldn't hand them to someone else.  I also do not want to risk my pets lives.  I work in human med and have seen far too often the things that can go wrong.  I would be afraid I could not get to the vet's office in time in the middle of the night.  That's me, though.  We are all different.  Makes the world go round. 
