I've name changed for this.
Jezebelz to quote you "ask any adoptive parent, any non birth mother, what is more important, truth or love?"
Do you have no understanding just how offensive your words are? I am so incredibly upset that you could even think this.
I am adopted and have known many fellow adoptees. We were all told that we were adopted as children and ALL of us have struggled with this knowledge. We have all struggled with understanding who we are, where we came from, how we fit in, we have all felt absolute worthlessness because we were not wanted by our birth parents (regardless of the reason behind our adoptions) and feelings of being unlovable.
As hard as the knowledge of our adoptions have been for us, it was our right to know the truth. Our human right.
The alternative of not knowing, of being forced to live a lie without our consent would have been both cruel and unbelievably damaging.
I was contacted by a charity in my late twenties asking if I was "my name" born on my DOB asking me to contact them as one of my birth parents was trying to find me. Can you imagine if I has not known of my adoption?
I have no familial medical history which has been important to know. I discovered I carried a genetic disorder when I was pregnant and had I not known I was adopted I certainly would have discovered it then. Can you imagine how devastating and stressful that would have been for me?
I know of one adoptee that if they had not known they were adopted and had discovered it due to a very serious medical reason they were going through, it would have destroyed them.
You have brought up your child with the truth. That they have two mummies. I do not know the age of your child but I assume that you will also tell them the truth of how they came to be conceived. That donor sperm was used. So that you both could have your loving family.
The welfare and rights of children should always come first. Lying to children about something so important as adoption or who their mother is (when known as many adoptions including mine were closed) is not in the children's best interest. Truth and facts are vital to childrens mental health.
So to answer your question the answer will always be TRUTH and LOVE.