The not trusting you would be my sticking point too.
Maybe you could just be super short and to the point and just say that although you understand her fears, you are MORE than capable of making business decisions in the best interest of the group and that if she has any personal issues against your choice of assistants, that the only thing you can offer her is a head's up when the assistant will be present and SHE can choose to stay home with child or bring child but the rate will remain the same.
I would also maybe add that while being a male in the early childhood field is not as common as females, you refuse to put that stereotypical thought process into a child's mind and are sad that you actually have to address it at all.
I'd be really upset if I were you at the lack of trust. For me personally that trust is so important in the provider-parent relationship.
I'm sorry this family is giving you such a hard time. Especially when you didn't have to go this far above and beyond.
