I am at a total loss as to how to address your comparison of being a fertile woman or how that has
anything to do with adopting a rescue
But I shall try to address is what you feel as someone dictating your pet ownership.
The reason there are so many animals that are in need of rescue is from irresponsible breeding and pet ownership. There are millions of animals killed every year because people like yourself feel it's their "right" to breed. Breeding should be looked upon as a privilege and should
only be done to accomplish bettering of the breed. It's disgusting to me to hear of puppies being sold in the local Walmart parking lot, all over Facebook, the internet, Kijji and a plethora of other questionable avenues to peddle puppies for a profit. Sure they had the right to breed but what does it accomplish?
I suggest you take a look in the Sick and Injured forum to see all of the poorly bred dogs that suffer from this need to breed? How about the local shelter and all of the millions of dogs that are PTS every year from this same "need to breed".
When a shelter or rescue stipulate that all animals within your home need to be spayed/neutered to be considered for adoption it is their right as well. They have the right to place any requirements upon you as a possible home for a dog in their care. This requirement is no different than a responsible breeder having a spay/neuter contract.
These same people see unfathomable heartache from all of these poor unwanted animals. They see dogs in horrible condition dumped, abused, neglected that they try to save. These same rescue have financial supporters that hold a standard of philosophical pet ownership and that does not include owning unaltered animals. Straight across the board~it's a basic requirement.
As for fostering with unaltered dog within your home let's address this as well. Many times the dogs that come into foster care are not altered as well. Their previous owners many times have used them to breed. Now you have a rescue in a foster situation with other unaltered animals. It's just a disaster waiting to happen. Being a foster home is not about the foster home it's about the well being of the little foster pup. Just the same way as being the owner of a rescue is about the well being of the rescue.
I wish you luck with wanting to rescue and foster but to be honest any rescue that would allow this to happen under your given situation should be under scrutiny.